update style of demo app

src/Net_40/HandyControl_Net_40/Themes/Styles/Base/TreeViewBaseStyle.xaml

@@ -51,7 +51,7 @@
                             <RowDefinition MinHeight="{StaticResource DefaultControlHeight}"/>
                             <RowDefinition/>
                         </Grid.RowDefinitions>
-                        <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
+                        <Border x:Name="Bd" CornerRadius="{Binding Path=(controls:BorderElement.CornerRadius),RelativeSource={RelativeSource TemplatedParent}}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
                             <StackPanel Orientation="Horizontal" Margin="{Binding Converter={StaticResource TreeViewItemMarginConverter}, RelativeSource={RelativeSource TemplatedParent}}">
                                 <ToggleButton x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>
                                 <ContentPresenter VerticalAlignment="Center" x:Name="PART_Header" ContentSource="Header" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>