support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Themes/Styles/SimpleItemsControl.xaml

@@ -0,0 +1,17 @@
+<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+                    xmlns:controls="clr-namespace:HandyControl.Controls">
+
+    <Style TargetType="controls:SimpleItemsControl">
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="controls:SimpleItemsControl">
+                    <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}">
+                        <StackPanel x:Name="PART_Panel" />
+                    </Border>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+</ResourceDictionary>