SharpDevelop/samples/XamlDesigner/Themes/Generic.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:Default="clr-namespace:ICSharpCode.XamlDesigner"
                    xmlns:Converters="clr-namespace:ICSharpCode.XamlDesigner.Converters">

    <Converters:LevelConverter x:Key="LevelConverter" />
    
    <Style TargetType="{x:Type Default:IconItem}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Default:IconItem}">
                    <StackPanel Orientation="Horizontal">
                        <Image Source="{TemplateBinding Icon}"
                               Stretch="None" />
                        <TextBlock Text="{TemplateBinding Text}"
                                   VerticalAlignment="Center"
                                   Margin="5 0 0 0" />
                    </StackPanel>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Brush x:Key="InsertBrush">#FFC73C</Brush>

    <Style x:Key="ExpandButtonStyle"
           TargetType="ToggleButton">
        <Setter Property="Focusable"
                Value="False" />
        <Setter Property="ClickMode"
                Value="Press" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ToggleButton">
                    <Border Background="Transparent">
                        <Border Width="9"
                                Height="9"
                                SnapsToDevicePixels="true"
                                BorderBrush="#FF7898B5"
                                BorderThickness="1"
                                CornerRadius="1">
                            <Border.Background>
                                <LinearGradientBrush EndPoint="1,1"
                                                     StartPoint="0,0">
                                    <GradientStop Color="White"
                                                  Offset=".2" />
                                    <GradientStop Color="#FFC0B7A6"
                                                  Offset="1" />
                                </LinearGradientBrush>
                            </Border.Background>
                            <Path Margin="1,1,1,1"
                                  x:Name="ExpandPath"
                                  Fill="Black"
                                  Data="M 0 2 L 0 3 L 2 3 L 2 5 L 3 5 L 3 3 L 5 3 L 5 2 L 3 2 L 3 0 L 2 0 L 2 2 Z" />
                        </Border>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsChecked"
                                 Value="True">
                            <Setter Property="Data"
                                    TargetName="ExpandPath"
                                    Value="M 0 2 L 0 3 L 5 3 L 5 2 Z" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{x:Type Default:DragTreeView}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Default:DragTreeView}">
                    <Grid Background="White">
                        <ScrollViewer HorizontalScrollBarVisibility="Auto"
                                      VerticalScrollBarVisibility="Auto">
                            <ItemsPresenter />
                        </ScrollViewer>
                        <Border x:Name="PART_InsertLine"
                                Background="{StaticResource InsertBrush}"
                                Height="2"
                                Width="50"
                                HorizontalAlignment="Left"
                                VerticalAlignment="Top"
                                Visibility="Collapsed"
                                IsHitTestVisible="False" />
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <Style TargetType="{x:Type Default:DragTreeViewItem}">
        <Setter Property="Foreground"
                Value="{x:Static SystemColors.ControlTextBrush}" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Default:DragTreeViewItem}">

                    <DockPanel Background="White">
                        <DockPanel x:Name="bg"
                                   DockPanel.Dock="Top"
                                   Background="{TemplateBinding Background}">
                            <ToggleButton x:Name="expandButton"
                                          Style="{StaticResource ExpandButtonStyle}"
                                          DockPanel.Dock="Left"
                                          Margin="{TemplateBinding Level, Converter={StaticResource LevelConverter}}"
                                          IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" />
                            <Border x:Name="contentBorder"
                                    HorizontalAlignment="Left">
                                <ContentPresenter x:Name="PART_Header"
                                                  ContentSource="Header" />
                            </Border>
                        </DockPanel>
                        <ItemsPresenter x:Name="itemsHost" />
                    </DockPanel>

                    <ControlTemplate.Triggers>
                        <Trigger Property="IsExpanded"
                                 Value="False">
                            <Setter TargetName="itemsHost"
                                    Property="Visibility"
                                    Value="Collapsed" />
                        </Trigger>
                        <Trigger Property="HasItems"
                                 Value="False">
                            <Setter TargetName="expandButton"
                                    Property="Visibility"
                                    Value="Hidden" />
                        </Trigger>
                        <Trigger Property="IsSelected"
                                 Value="True">
                            <Setter TargetName="bg"
                                    Property="Background"
                                    Value="{x:Static SystemColors.HighlightBrush}" />
                            <Setter Property="Foreground"
                                    Value="{x:Static SystemColors.HighlightTextBrush}" />
                        </Trigger>
                        <Trigger Property="IsDragHover"
                                 Value="True">
                            <Setter TargetName="contentBorder"
                                    Property="Background"
                                    Value="{StaticResource InsertBrush}" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>