sourcegit/src/Resources/Styles/ContextMenu.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Style TargetType="{x:Type MenuItem}">
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="BorderThickness" Value="0"/>
        <Setter Property="Foreground" Value="{DynamicResource Brush.FG1}"/>
        <Setter Property="MinHeight" Value="24"/>
        <Setter Property="SnapsToDevicePixels" Value="True"/>
        <Setter Property="TextOptions.TextFormattingMode" Value="Display"/>
        <Setter Property="TextOptions.TextRenderingMode" Value="ClearType"/>
        <Setter Property="RenderOptions.ClearTypeHint" Value="Enabled"/>
    </Style>
    
    <Style TargetType="{x:Type ContextMenu}">
        <Setter Property="SnapsToDevicePixels" Value="True" />
        <Setter Property="Grid.IsSharedSizeScope" Value="False" />
        <Setter Property="HorizontalOffset" Value="-4"/>
        <Setter Property="VerticalOffset" Value="-4"/>
        <Setter Property="TextElement.FontSize" Value="13"/>

        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ContextMenu}">
                    <Grid>
                        <Border Background="{DynamicResource Brush.Popup}" BorderThickness="0" Margin="4">
                            <Border.Effect>
                                <DropShadowEffect BlurRadius="4" ShadowDepth="0" Color="Black" Opacity=".8"/>
                            </Border.Effect>
                        </Border>
                        <StackPanel IsItemsHost="True" Margin="6" KeyboardNavigation.DirectionalNavigation="Cycle"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <ControlTemplate x:Key="{x:Static MenuItem.SubmenuItemTemplateKey}" TargetType="{x:Type MenuItem}">
        <Border Name="Border" Background="Transparent">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="32"/>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition Width="16"/>
                </Grid.ColumnDefinitions>

                <ContentPresenter Name="Icon" Grid.Column="0" HorizontalAlignment="Center" ContentSource="Icon"/>
                <ContentPresenter Name="HeadHost" Grid.Column="1" ContentSource="Header" VerticalAlignment="Center"/>
            </Grid>
        </Border>

        <ControlTemplate.Triggers>
            <Trigger Property="IsMouseOver" Value="True">
                <Setter TargetName="Border" Property="Background" Value="{DynamicResource Brush.Accent2}"/>
            </Trigger>
            <Trigger Property="IsEnabled" Value="False">
                <Setter Property="Opacity" Value=".5"/>
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>

    <ControlTemplate x:Key="{x:Static MenuItem.SubmenuHeaderTemplateKey}" TargetType="{x:Type MenuItem}">
        <Border Name="Border" Background="Transparent">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="32"/>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition Width="16"/>
                </Grid.ColumnDefinitions>

                <ContentPresenter Name="Icon" Grid.Column="0" Margin="6,0" VerticalAlignment="Center" ContentSource="Icon"/>
                <ContentPresenter Name="HeadHost" Grid.Column="1" Margin="0,0,8,0" ContentSource="Header" VerticalAlignment="Center"/>
                <Path Grid.Column="2" Width="8" Height="8" Style="{DynamicResource Style.Icon}" Data="M 0 0 L 0 7 L 4 3.5 Z"/>
                <Popup Name="Popup" Placement="Right" HorizontalOffset="-4" VerticalOffset="-4" IsOpen="{TemplateBinding IsSubmenuOpen}" AllowsTransparency="True" Focusable="False" PopupAnimation="Fade">
                    <Grid>
                        <Border Background="{DynamicResource Brush.Popup}" BorderThickness="0" Margin="4">
                            <Border.Effect>
                                <DropShadowEffect BlurRadius="4" ShadowDepth="0" Color="Black" Opacity=".8"/>
                            </Border.Effect>
                        </Border>

                        <ScrollViewer Margin="6" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto" CanContentScroll="True">
                            <StackPanel IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Cycle"/>
                        </ScrollViewer>
                    </Grid>
                </Popup>
            </Grid>
        </Border>

        <ControlTemplate.Triggers>
            <Trigger Property="IsHighlighted" Value="True">
                <Setter TargetName="Border" Property="Background" Value="{DynamicResource Brush.Accent2}"/>
            </Trigger>
            <Trigger Property="IsEnabled" Value="False">
                <Setter Property="Opacity" Value=".5"/>
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>

    <Style x:Key="{x:Static MenuItem.SeparatorStyleKey}" TargetType="{x:Type Separator}">
        <Setter Property="Margin" Value="30,2,0,2"/>
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Separator}">
                    <Rectangle Height=".8" VerticalAlignment="Center" SnapsToDevicePixels="True" Fill="{DynamicResource Brush.Border2}"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>