From ff70553244601bee5a0862ca53deff774184436b Mon Sep 17 00:00:00 2001
From: NaBian <836904362@qq.com>
Date: Sun, 17 Jan 2021 23:28:45 +0800
Subject: [PATCH] update ComboBox Style with Empty control

---
 .../Themes/Styles/Base/ComboBoxBaseStyle.xaml | 308 ++++++++--------
 .../HandyControl_Net_40/Themes/Theme.xaml     | 314 ++++++++---------
 .../Themes/Styles/Base/ComboBoxBaseStyle.xaml | 308 ++++++++--------
 .../HandyControl_Shared/Themes/Theme.xaml     | 332 ++++++++----------
 4 files changed, 577 insertions(+), 685 deletions(-)

diff --git a/src/Net_40/HandyControl_Net_40/Themes/Styles/Base/ComboBoxBaseStyle.xaml b/src/Net_40/HandyControl_Net_40/Themes/Styles/Base/ComboBoxBaseStyle.xaml
index 90e32bcf..e64263e5 100644
--- a/src/Net_40/HandyControl_Net_40/Themes/Styles/Base/ComboBoxBaseStyle.xaml
+++ b/src/Net_40/HandyControl_Net_40/Themes/Styles/Base/ComboBoxBaseStyle.xaml
@@ -82,14 +82,16 @@
             </Grid.ColumnDefinitions>
             <Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{Binding Background,RelativeSource={RelativeSource TemplatedParent}}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
@@ -109,10 +111,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -149,14 +147,16 @@
             </StackPanel>
             <Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -176,10 +176,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -214,14 +210,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -241,10 +239,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -293,14 +287,16 @@
             </Grid.ColumnDefinitions>
             <Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
@@ -320,10 +316,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
                 <Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}"/>
             </Trigger>
@@ -360,14 +352,16 @@
             </StackPanel>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -387,10 +381,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
                 <Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}"/>
             </Trigger>
@@ -425,14 +415,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -452,10 +444,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -599,14 +587,16 @@
             </StackPanel>
             <Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1"/>
@@ -628,10 +618,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -704,14 +690,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="1" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}"/>
@@ -733,10 +721,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -812,14 +796,16 @@
             </StackPanel>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1"/>
@@ -841,10 +827,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -937,26 +919,30 @@
             </StackPanel>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" StaysOpen="False" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}"/>
-                            </Canvas>
-                            <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1"/>
@@ -983,14 +969,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder_AutoComplete" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder_AutoComplete" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -1081,14 +1059,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}"/>
@@ -1110,10 +1090,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -1203,26 +1179,30 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <Popup Grid.Column="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}"/>
-                            </Canvas>
-                            <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}"/>
@@ -1249,14 +1229,6 @@
                 <Setter Property="MaxWidth" TargetName="dropDownBorder_AutoComplete" Value="{x:Static system:Double.MaxValue}" />
                 <Setter Property="MinWidth" TargetName="dropDownBorder_AutoComplete" Value="{Binding ActualHeight, ElementName=toggleButton}" />
             </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
diff --git a/src/Net_40/HandyControl_Net_40/Themes/Theme.xaml b/src/Net_40/HandyControl_Net_40/Themes/Theme.xaml
index cbbcab06..fd655cf3 100644
--- a/src/Net_40/HandyControl_Net_40/Themes/Theme.xaml
+++ b/src/Net_40/HandyControl_Net_40/Themes/Theme.xaml
@@ -4514,14 +4514,16 @@
 			</Grid.ColumnDefinitions>
 			<Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{Binding Background,RelativeSource={RelativeSource TemplatedParent}}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}" />
@@ -4541,10 +4543,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -4579,14 +4577,16 @@
 			</StackPanel>
 			<Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4606,10 +4606,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -4642,14 +4638,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4669,10 +4667,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -4717,14 +4711,16 @@
 			</Grid.ColumnDefinitions>
 			<Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}" />
@@ -4744,10 +4740,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
 				<Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}" />
 			</Trigger>
@@ -4782,14 +4774,16 @@
 			</StackPanel>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4809,10 +4803,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
 				<Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}" />
 			</Trigger>
@@ -4845,14 +4835,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4872,10 +4864,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5011,14 +4999,16 @@
 			</StackPanel>
 			<Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1" />
@@ -5040,10 +5030,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -5114,14 +5100,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="1" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" />
@@ -5143,10 +5131,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -5220,14 +5204,16 @@
 			</StackPanel>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1" />
@@ -5249,10 +5235,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5344,26 +5326,30 @@
 			</StackPanel>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" StaysOpen="False" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}" />
-							</Canvas>
-							<StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1" />
@@ -5390,14 +5376,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder_AutoComplete" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder_AutoComplete" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5486,14 +5464,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" />
@@ -5515,10 +5495,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5607,26 +5583,30 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<Popup Grid.Column="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}" />
-							</Canvas>
-							<StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" />
@@ -5653,14 +5633,6 @@
 				<Setter Property="MaxWidth" TargetName="dropDownBorder_AutoComplete" Value="{x:Static system:Double.MaxValue}" />
 				<Setter Property="MinWidth" TargetName="dropDownBorder_AutoComplete" Value="{Binding ActualHeight, ElementName=toggleButton}" />
 			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -8219,9 +8191,9 @@
 	<DrawingBrush x:Key="EmptySimpleLogo" o:Freeze="True">
 		<DrawingBrush.Drawing>
 			<DrawingGroup o:Freeze="True">
-				<GeometryDrawing o:Freeze="True" Brush="{DynamicResource RegionBrush}" Geometry="F1 M1638,1024z M0,0z M0,844.8C0,942.250667 361.096533,1021.269333 806.536533,1021.269333 1251.976533,1021.269333 1613.038933,942.250666 1613.038933,844.8 1613.038933,747.383467 1251.9424,668.398933 806.536533,668.398933 361.096533,668.398933 0,747.383467 0,844.8z" />
+				<GeometryDrawing o:Freeze="True" Brush="{DynamicResource SecondaryRegionBrush}" Geometry="F1 M1638,1024z M0,0z M0,844.8C0,942.250667 361.096533,1021.269333 806.536533,1021.269333 1251.976533,1021.269333 1613.038933,942.250666 1613.038933,844.8 1613.038933,747.383467 1251.9424,668.398933 806.536533,668.398933 361.096533,668.398933 0,747.383467 0,844.8z" />
 				<GeometryDrawing o:Freeze="True" Brush="{DynamicResource BorderBrush}" Geometry="F1 M1638,1024z M0,0z M1398.784,580.164267L214.254933,580.164267 214.254933,330.6496 473.873067,35.771733C486.4,13.1072,509.1328,0.477867,531.797333,0.477867L1081.2416,0.477867C1103.940267,0.477867,1126.638933,13.1072,1141.725867,38.2976L1398.818133,330.6496 1398.818133,580.164267z M239.479467,555.008L1373.627733,555.008 1373.627733,338.261333 1121.553067,50.858667C1108.992,33.245867,1096.362667,23.210667,1081.2416,23.210667L531.797333,23.210667C516.676266,23.210667,504.081066,33.28,493.9776,48.401067L239.445333,340.753067 239.445333,554.973867z" />
-				<GeometryDrawing o:Freeze="True" Brush="{DynamicResource RegionBrush}" Geometry="F1 M1638,1024z M0,0z M1048.4736,413.832533C1048.4736,373.521066,1073.664,340.753066,1103.940267,340.753067L1386.222933,340.753067 1386.222933,796.945067C1386.222933,849.851734,1353.454933,895.249067,1310.583467,895.249067L302.455467,895.249067C262.109867,895.249067,226.850134,852.3776,226.850133,796.945067L226.850133,340.753067 509.1328,340.753067C539.374933,340.753067 564.565333,373.521067 564.565333,413.832533 564.565333,454.143999 589.755733,486.912 619.997867,486.912L993.041067,486.912C1023.2832,489.437867,1048.4736,454.144,1048.4736,413.832533z" />
+				<GeometryDrawing o:Freeze="True" Brush="{DynamicResource SecondaryRegionBrush}" Geometry="F1 M1638,1024z M0,0z M1048.4736,413.832533C1048.4736,373.521066,1073.664,340.753066,1103.940267,340.753067L1386.222933,340.753067 1386.222933,796.945067C1386.222933,849.851734,1353.454933,895.249067,1310.583467,895.249067L302.455467,895.249067C262.109867,895.249067,226.850134,852.3776,226.850133,796.945067L226.850133,340.753067 509.1328,340.753067C539.374933,340.753067 564.565333,373.521067 564.565333,413.832533 564.565333,454.143999 589.755733,486.912 619.997867,486.912L993.041067,486.912C1023.2832,489.437867,1048.4736,454.144,1048.4736,413.832533z" />
 				<GeometryDrawing o:Freeze="True" Brush="{DynamicResource BorderBrush}" Geometry="F1 M1638,1024z M0,0z M1310.583467,907.844267L302.455467,907.844267C254.5664,907.844267,214.2208,857.429334,214.2208,796.910933L214.2208,328.192 509.1328,328.192C546.9184,328.192 577.160533,365.9776 577.160533,413.866667 577.160533,446.634667 597.2992,474.350934 619.997867,474.350933L993.041067,474.350933C1015.7056,474.350933 1035.8784,446.634666 1035.8784,413.866667 1035.8784,365.9776 1066.120533,328.192 1103.940267,328.192L1398.818133,328.192 1398.818133,796.9792C1398.818133,857.463467,1360.9984,907.8784,1310.583467,907.8784z M239.445333,353.348267L239.445333,796.945067C239.445333,844.834134,267.1616,882.619734,302.455467,882.619733L1310.583467,882.619733C1345.877334,882.619733,1373.5936,844.834133,1373.5936,796.945067L1373.5936,353.348267 1103.940267,353.348267C1081.2416,353.348267 1061.0688,381.064534 1061.0688,413.832533 1061.0688,461.7216 1030.826667,499.5072 993.041067,499.5072L619.997867,499.5072C582.212267,499.5072 551.970134,461.7216 551.970133,413.832533 551.970133,381.064533 531.831466,350.8224 509.1328,350.8224L239.445333,350.8224 239.445333,353.348267z" />
 			</DrawingGroup>
 		</DrawingBrush.Drawing>
@@ -11102,7 +11074,7 @@
 		<Setter Property="Template">
 			<Setter.Value>
 				<ControlTemplate TargetType="TreeView">
-					<Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="true">
+					<Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="true">
 						<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
 							<hc:ToggleBlock.CheckedContent>
 								<hc:ScrollViewer x:Name="_tv_scrollviewer_" IsInertiaEnabled="{Binding Path=(hc:ScrollViewer.IsInertiaEnabled),RelativeSource={RelativeSource TemplatedParent}}" Template="{StaticResource ScrollViewerBaseControlTemplate}" Background="{TemplateBinding Background}" CanContentScroll="false" Focusable="false" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}">
diff --git a/src/Shared/HandyControl_Shared/Themes/Styles/Base/ComboBoxBaseStyle.xaml b/src/Shared/HandyControl_Shared/Themes/Styles/Base/ComboBoxBaseStyle.xaml
index ee309422..81a2d478 100644
--- a/src/Shared/HandyControl_Shared/Themes/Styles/Base/ComboBoxBaseStyle.xaml
+++ b/src/Shared/HandyControl_Shared/Themes/Styles/Base/ComboBoxBaseStyle.xaml
@@ -82,14 +82,16 @@
             </Grid.ColumnDefinitions>
             <Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{Binding Background,RelativeSource={RelativeSource TemplatedParent}}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
@@ -116,10 +118,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -156,14 +154,16 @@
             </StackPanel>
             <Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -190,10 +190,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -228,14 +224,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -262,10 +260,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -314,14 +308,16 @@
             </Grid.ColumnDefinitions>
             <Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
@@ -348,10 +344,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
                 <Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}"/>
             </Trigger>
@@ -388,14 +380,16 @@
             </StackPanel>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -422,10 +416,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
                 <Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}"/>
             </Trigger>
@@ -460,14 +450,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}"/>
@@ -494,10 +486,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -641,14 +629,16 @@
             </StackPanel>
             <Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1"/>
@@ -677,10 +667,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -753,14 +739,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="1" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}"/>
@@ -789,10 +777,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="toggleButton"/>
@@ -868,14 +852,16 @@
             </StackPanel>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1"/>
@@ -904,10 +890,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -1000,26 +982,30 @@
             </StackPanel>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" StaysOpen="False" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}"/>
-                            </Canvas>
-                            <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1"/>
@@ -1053,14 +1039,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -1151,14 +1129,16 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}"/>
@@ -1187,10 +1167,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
@@ -1280,26 +1256,30 @@
             </StackPanel>
             <Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
-                            </Canvas>
-                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <Popup Grid.Column="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                 <Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-                    <ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-                        <hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-                                <Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}"/>
-                            </Canvas>
-                            <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </hc:SimplePanel>
-                    </ScrollViewer>
+                    <hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+                        <hc:ToggleBlock.CheckedContent>
+                            <ScrollViewer Margin="0,4">
+                                <StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
+                            </ScrollViewer>
+                        </hc:ToggleBlock.CheckedContent>
+                        <hc:ToggleBlock.UnCheckedContent>
+                            <hc:Empty/>
+                        </hc:ToggleBlock.UnCheckedContent>
+                    </hc:ToggleBlock>
                 </Border>
             </Popup>
             <TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}"/>
@@ -1333,14 +1313,6 @@
                 </MultiTrigger.Conditions>
                 <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
             </MultiTrigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
-            </Trigger>
-            <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-                <Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-                <Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}"/>
-            </Trigger>
             <MultiTrigger>
                 <MultiTrigger.Conditions>
                     <Condition Property="IsMouseOver" Value="true" SourceName="border"/>
diff --git a/src/Shared/HandyControl_Shared/Themes/Theme.xaml b/src/Shared/HandyControl_Shared/Themes/Theme.xaml
index f333bda3..88df14ed 100644
--- a/src/Shared/HandyControl_Shared/Themes/Theme.xaml
+++ b/src/Shared/HandyControl_Shared/Themes/Theme.xaml
@@ -4513,14 +4513,16 @@
 			</Grid.ColumnDefinitions>
 			<Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{Binding Background,RelativeSource={RelativeSource TemplatedParent}}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}" />
@@ -4547,10 +4549,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -4585,14 +4583,16 @@
 			</StackPanel>
 			<Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4619,10 +4619,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -4655,14 +4651,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4689,10 +4687,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -4737,14 +4731,16 @@
 			</Grid.ColumnDefinitions>
 			<Popup x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}" />
@@ -4771,10 +4767,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
 				<Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}" />
 			</Trigger>
@@ -4809,14 +4801,16 @@
 			</StackPanel>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Row="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" Grid.Column="0" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4843,10 +4837,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<Trigger Property="IsMouseOver" Value="true" SourceName="PART_EditableTextBox">
 				<Setter Property="BorderBrush" Value="{DynamicResource SecondaryBorderBrush}" />
 			</Trigger>
@@ -4879,14 +4869,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<ToggleButton Grid.Column="1" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" Content="{Binding Path=(hc:InfoElement.Placeholder),RelativeSource={RelativeSource TemplatedParent}}" x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxWatermarkToggleButton}" />
@@ -4913,10 +4905,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5052,14 +5040,16 @@
 			</StackPanel>
 			<Popup Grid.Row="1" Grid.Column="0" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1" />
@@ -5088,10 +5078,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -5162,14 +5148,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="1" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" />
@@ -5198,10 +5186,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="toggleButton" />
@@ -5275,14 +5259,16 @@
 			</StackPanel>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1" />
@@ -5311,10 +5297,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5406,26 +5388,30 @@
 			</StackPanel>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<Popup Grid.Column="0" Grid.Row="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" StaysOpen="False" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}" />
-							</Canvas>
-							<StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="0" Grid.ColumnSpan="2" FontSize="12" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" Grid.Row="1" />
@@ -5459,14 +5445,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5555,14 +5533,16 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" />
@@ -5591,10 +5571,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -5683,26 +5659,30 @@
 			</StackPanel>
 			<Popup Grid.Column="1" x:Name="PART_Popup" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}" />
-							</Canvas>
-							<ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<Popup Grid.Column="1" x:Name="PART_Popup_AutoComplete" PlacementTarget="{Binding ElementName=toggleButton}" AllowsTransparency="true" Grid.ColumnSpan="2" PopupAnimation="{StaticResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
 				<Border CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" x:Name="dropDownBorder_AutoComplete" MinWidth="{Binding ActualWidth, ElementName=toggleButton}" MaxHeight="{TemplateBinding MaxDropDownHeight}" BorderBrush="{DynamicResource BorderBrush}" BorderThickness="1" Background="{DynamicResource RegionBrush}">
-					<ScrollViewer Margin="0,4" x:Name="DropDownScrollViewer_AutoComplete">
-						<hc:SimplePanel RenderOptions.ClearTypeHint="Enabled">
-							<Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
-								<Rectangle x:Name="opaqueRect_AutoComplete" Fill="{Binding Background, ElementName=dropDownBorder_AutoComplete}" Height="{Binding ActualHeight, ElementName=dropDownBorder_AutoComplete}" Width="{Binding ActualWidth, ElementName=dropDownBorder_AutoComplete}" />
-							</Canvas>
-							<StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						</hc:SimplePanel>
-					</ScrollViewer>
+					<hc:ToggleBlock IsChecked="{Binding HasItems,RelativeSource={RelativeSource TemplatedParent},Mode=OneWay}" VerticalContentAlignment="Stretch" HorizontalContentAlignment="Stretch">
+						<hc:ToggleBlock.CheckedContent>
+							<ScrollViewer Margin="0,4">
+								<StackPanel Name="PART_AutoCompletePanel" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+						</hc:ToggleBlock.CheckedContent>
+						<hc:ToggleBlock.UnCheckedContent>
+							<hc:Empty />
+						</hc:ToggleBlock.UnCheckedContent>
+					</hc:ToggleBlock>
 				</Border>
 			</Popup>
 			<TextBlock Grid.Column="1" Grid.ColumnSpan="2" Text="{TemplateBinding ErrorStr}" Name="TextBlockError" VerticalAlignment="Bottom" Margin="9,0,0,4" Foreground="{DynamicResource DangerBrush}" />
@@ -5736,14 +5716,6 @@
 				</MultiTrigger.Conditions>
 				<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
 			</MultiTrigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}" />
-			</Trigger>
-			<Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer_AutoComplete" Value="false">
-				<Setter Property="Canvas.Top" TargetName="opaqueRect_AutoComplete" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-				<Setter Property="Canvas.Left" TargetName="opaqueRect_AutoComplete" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer_AutoComplete}" />
-			</Trigger>
 			<MultiTrigger>
 				<MultiTrigger.Conditions>
 					<Condition Property="IsMouseOver" Value="true" SourceName="border" />
@@ -12095,23 +12067,27 @@
 							</DoubleAnimationUsingKeyFrames>
 						</Storyboard>
 					</ControlTemplate.Resources>
-					<Grid>
+					<Grid Background="{TemplateBinding Background}" SnapsToDevicePixels="True">
 						<Grid.ColumnDefinitions>
 							<ColumnDefinition Width="*" />
 							<ColumnDefinition Width="Auto" />
 						</Grid.ColumnDefinitions>
 						<Grid.RowDefinitions>
-							<RowDefinition Height="Auto" />
 							<RowDefinition Height="*" />
+							<RowDefinition Height="Auto" />
 						</Grid.RowDefinitions>
-						<GridViewHeaderRowPresenter AllowsColumnReorder="{Binding TemplatedParent.View.AllowsColumnReorder, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderContainerStyle="{Binding TemplatedParent.View.ColumnHeaderContainerStyle, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderToolTip="{Binding TemplatedParent.View.ColumnHeaderToolTip, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderContextMenu="{Binding TemplatedParent.View.ColumnHeaderContextMenu, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderTemplate="{Binding TemplatedParent.View.ColumnHeaderTemplate, RelativeSource={RelativeSource TemplatedParent}}" Columns="{Binding TemplatedParent.View.Columns, RelativeSource={RelativeSource TemplatedParent}}" />
-						<ScrollContentPresenter Grid.ColumnSpan="2" Grid.Column="0" Grid.Row="1" x:Name="PART_ScrollContentPresenter" CanContentScroll="{TemplateBinding CanContentScroll}" CanHorizontallyScroll="False" CanVerticallyScroll="False" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" KeyboardNavigation.DirectionalNavigation="Local" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-						<!--<DockPanel Margin="{TemplateBinding Padding}" Grid.RowSpan="2" Grid.ColumnSpan="2">
-                            <GridViewHeaderRowPresenter DockPanel.Dock="Top" AllowsColumnReorder="{Binding TemplatedParent.View.AllowsColumnReorder, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderContainerStyle="{Binding TemplatedParent.View.ColumnHeaderContainerStyle, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderToolTip="{Binding TemplatedParent.View.ColumnHeaderToolTip, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderContextMenu="{Binding TemplatedParent.View.ColumnHeaderContextMenu, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderTemplate="{Binding TemplatedParent.View.ColumnHeaderTemplate, RelativeSource={RelativeSource TemplatedParent}}" Columns="{Binding TemplatedParent.View.Columns, RelativeSource={RelativeSource TemplatedParent}}" Margin="2,0" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                            <ScrollContentPresenter x:Name="PART_ScrollContentPresenter" CanContentScroll="{TemplateBinding CanContentScroll}" CanHorizontallyScroll="False" CanVerticallyScroll="False" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" KeyboardNavigation.DirectionalNavigation="Local" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
-                        </DockPanel>-->
-						<ScrollBar Style="{StaticResource ScrollBarBaseStyle}" Opacity="0" x:Name="PART_VerticalScrollBar" Grid.Column="1" Maximum="{TemplateBinding ScrollableHeight}" Orientation="Vertical" Grid.Row="1" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Value="{Binding VerticalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportHeight}" />
-						<ScrollBar Style="{StaticResource ScrollBarBaseStyle}" Opacity="0" x:Name="PART_HorizontalScrollBar" Grid.Column="0" Maximum="{TemplateBinding ScrollableWidth}" Orientation="Horizontal" VerticalAlignment="Bottom" Grid.Row="1" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" Value="{Binding HorizontalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportWidth}" />
+						<DockPanel Margin="{TemplateBinding Padding}" Grid.RowSpan="2" Grid.ColumnSpan="2">
+							<ScrollViewer DockPanel.Dock="Top" Focusable="False" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden">
+								<GridViewHeaderRowPresenter AllowsColumnReorder="{Binding TemplatedParent.View.AllowsColumnReorder, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderContainerStyle="{Binding TemplatedParent.View.ColumnHeaderContainerStyle, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderToolTip="{Binding TemplatedParent.View.ColumnHeaderToolTip, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderContextMenu="{Binding TemplatedParent.View.ColumnHeaderContextMenu, RelativeSource={RelativeSource TemplatedParent}}" ColumnHeaderTemplate="{Binding TemplatedParent.View.ColumnHeaderTemplate, RelativeSource={RelativeSource TemplatedParent}}" Columns="{Binding TemplatedParent.View.Columns, RelativeSource={RelativeSource TemplatedParent}}" Margin="2,0" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+							</ScrollViewer>
+							<ScrollContentPresenter x:Name="PART_ScrollContentPresenter" CanContentScroll="{TemplateBinding CanContentScroll}" CanHorizontallyScroll="False" CanVerticallyScroll="False" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" KeyboardNavigation.DirectionalNavigation="Local" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+						</DockPanel>
+						<ScrollBar x:Name="PART_VerticalScrollBar" Opacity="0" Style="{StaticResource ScrollBarBaseStyle}" Cursor="Arrow" Grid.Column="1" Maximum="{TemplateBinding ScrollableHeight}" Minimum="0" Grid.Row="0" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Value="{Binding VerticalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportHeight}" />
+						<ScrollBar x:Name="PART_HorizontalScrollBar" Opacity="0" Style="{StaticResource ScrollBarBaseStyle}" Cursor="Arrow" Grid.Column="0" Maximum="{TemplateBinding ScrollableWidth}" Minimum="0" Orientation="Horizontal" Grid.Row="1" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" Value="{Binding HorizontalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportWidth}" />
+						<DockPanel Background="{Binding Background, ElementName=PART_VerticalScrollBar}" Grid.Column="1" LastChildFill="False" Grid.Row="1">
+							<Rectangle DockPanel.Dock="Left" Fill="White" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Width="1" />
+							<Rectangle DockPanel.Dock="Top" Fill="White" Height="1" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" />
+						</DockPanel>
 					</Grid>
 					<ControlTemplate.Triggers>
 						<EventTrigger RoutedEvent="MouseEnter">