QuickLook/QuickLook.Plugin/QuickLook.Plugin.TextViewer/Controls/DropDownButton.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:local="clr-namespace:ICSharpCode.AvalonEdit.Search;assembly=ICSharpCode.AvalonEdit">

    <!--  Colors for DropDownButton and SplitButton  -->
    <SolidColorBrush x:Key="{ComponentResourceKey {x:Type local:DropDownButton}, ActiveBorder}" Color="#FF0A246A" />
    <SolidColorBrush x:Key="{ComponentResourceKey {x:Type local:DropDownButton}, ActiveBackground}" Color="#FFB6BDD2" />

    <!--  Style and Template for DropDownButton  -->
    <Style TargetType="{x:Type local:DropDownButton}">
        <!--<Setter Property="TextElement.Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" />-->
        <Setter Property="Control.Padding" Value="2,2,2,2" />
        <Setter Property="Border.BorderThickness" Value="1,1,1,1" />
        <Setter Property="Panel.Background" Value="Transparent" />
        <Setter Property="Border.BorderBrush" Value="Transparent" />
        <Setter Property="FrameworkElement.HorizontalAlignment" Value="Center" />
        <Setter Property="FrameworkElement.VerticalAlignment" Value="Center" />
        <Setter Property="Control.HorizontalContentAlignment" Value="Center" />
        <Setter Property="Control.VerticalContentAlignment" Value="Center" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate xmlns:s="clr-namespace:System;assembly=mscorlib" TargetType="local:DropDownButton">
                    <Border Name="OuterBorder"
                            Background="{TemplateBinding Panel.Background}"
                            BorderBrush="{TemplateBinding Border.BorderBrush}"
                            BorderThickness="{TemplateBinding Border.BorderThickness}"
                            SnapsToDevicePixels="True">
                        <StackPanel Orientation="Horizontal">
                            <ContentPresenter Margin="{TemplateBinding Control.Padding}"
                                              HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
                                              VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}"
                                              Content="{TemplateBinding ContentControl.Content}"
                                              ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}"
                                              ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}"
                                              SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
                            <!--  CaretDownSolid8  -->
                            <TextBlock Width="6"
                                       Margin="0,2,2,2"
                                       HorizontalAlignment="Center"
                                       VerticalAlignment="Center"
                                       FontFamily="{DynamicResource SymbolThemeFontFamily}"
                                       FontSize="6"
                                       Foreground="{DynamicResource TextFillColorPrimaryBrush}"
                                       Text="&#xeddc;" />
                        </StackPanel>
                    </Border>
                    <ControlTemplate.Triggers>
                        <!--<Trigger Property="UIElement.IsMouseOver" Value="True">
                            <Setter TargetName="OuterBorder" Property="Border.BorderBrush" Value="{DynamicResource {ComponentResourceKey {x:Type local:DropDownButton}, ActiveBorder}}" />
                            <Setter TargetName="OuterBorder" Property="Panel.Background" Value="{DynamicResource {ComponentResourceKey {x:Type local:DropDownButton}, ActiveBackground}}" />
                        </Trigger>-->
                        <!--<Trigger Property="UIElement.IsKeyboardFocused" Value="True">
                            <Setter TargetName="OuterBorder" Property="Border.BorderBrush" Value="{DynamicResource {ComponentResourceKey {x:Type local:DropDownButton}, ActiveBorder}}" />
                            <Setter TargetName="OuterBorder" Property="Panel.Background" Value="{DynamicResource {ComponentResourceKey {x:Type local:DropDownButton}, ActiveBackground}}" />
                        </Trigger>-->
                        <!--<Trigger Property="UIElement.IsEnabled" Value="False">
                            <Setter Property="TextElement.Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
                        </Trigger>-->
                        <!--<Trigger Property="local:DropDownButton.IsDropDownContentOpen" Value="True">
                            <Setter TargetName="OuterBorder" Property="Border.BorderBrush" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}" />
                            <Setter TargetName="OuterBorder" Property="Border.BorderThickness" Value="1,1,1,0" />
                            <Setter TargetName="OuterBorder" Property="Border.Padding" Value="0,0,0,1" />
                            <Setter TargetName="OuterBorder" Property="Panel.Background" Value="Transparent" />
                        </Trigger>-->
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>