A WPF SplitButton

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:s="clr-namespace:Wpf.Controls"
    xmlns:luna="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Luna">

	<Style x:Key="ButtonFocusVisual">
		<Setter Property="Control.Template">
			<Setter.Value>
				<ControlTemplate>
					<Rectangle SnapsToDevicePixels="true" Margin="3" Stroke="Black" StrokeDashArray="1 2" StrokeThickness="1"/>
				</ControlTemplate>
			</Setter.Value>
		</Setter>
	</Style>

	<LinearGradientBrush x:Key="ButtonNormalBackground" EndPoint="0,1" StartPoint="0,0">
		<GradientStop Color="#FFFFFFFF" Offset="0"/>
		<GradientStop Color="#FFF3EEDB" Offset="0.9"/>
	</LinearGradientBrush>
	<SolidColorBrush x:Key="ButtonNormalBorder" Color="#FF376206"/>

	<Style x:Key="lunaHomesteadDropDownStyle" TargetType="{x:Type Button}">
		<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
		<Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/>
		<Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/>
		<Setter Property="Template">
			<Setter.Value>
				<ControlTemplate TargetType="{x:Type Button}">
					<Grid Background="Transparent" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
						<luna:ButtonChrome x:Name="chrome" 
							BorderBrush="{TemplateBinding BorderBrush}"
							Fill="{TemplateBinding Background}"
							HorizontalAlignment="Stretch" 
							VerticalAlignment="Stretch"
							RenderMouseOver="{TemplateBinding IsMouseOver}"
							RenderPressed="{TemplateBinding IsPressed}"
							RenderDefaulted="{TemplateBinding IsDefaulted}"
							SnapsToDevicePixels="True">
							<ContentPresenter x:Name="Cp" HorizontalAlignment="Center" VerticalAlignment="Center"/>
						</luna:ButtonChrome>
					</Grid>
					<ControlTemplate.Triggers>
						<Trigger Property="IsEnabled" Value="false">
							<Setter Property="Path.Stroke" TargetName="Cp" Value="#ADADAD"/>
							<Setter Property="Path.Fill" TargetName="Cp" Value="#ADADAD"/>
						</Trigger>
					</ControlTemplate.Triggers>
				</ControlTemplate>
			</Setter.Value>
		</Setter>
	</Style>

	<Style TargetType="{x:Type s:SplitButton}">
		<Setter Property="FocusVisualStyle" Value="{StaticResource ButtonFocusVisual}"/>
		<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
		<Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/>
		<Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/>
		<Setter Property="HorizontalContentAlignment" Value="Center"/>
		<Setter Property="VerticalContentAlignment" Value="Center"/>
		<Setter Property="Padding" Value="0"/>
		<Setter Property="Template">
			<Setter.Value>
				<ControlTemplate TargetType="{x:Type s:SplitButton}">
					<Grid>
						<luna:ButtonChrome x:Name="buttonChrome" 
							HorizontalAlignment="Stretch" 
							VerticalAlignment="Stretch"
							BorderBrush="{TemplateBinding BorderBrush}"
							Fill="{TemplateBinding Background}"
							RenderMouseOver="{TemplateBinding IsMouseOver}"
							RenderPressed="{TemplateBinding IsContextMenuOpen}"
							RenderDefaulted="{TemplateBinding IsDefaulted}"
							SnapsToDevicePixels="True">

							<Grid Background="Transparent" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
								<Grid.ColumnDefinitions>
									<ColumnDefinition Width="*"/>
									<ColumnDefinition Width="16"/>
								</Grid.ColumnDefinitions>
								
								<Border x:Name="Bd" Margin="1,0,1,0">
									<ContentPresenter
										HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
										VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
										Margin="{TemplateBinding Padding}"
										RecognizesAccessKey="True"
										/>
								</Border>

								<Path x:Name="path"
									Data="M0,0L3,3 6,0z" 
									Margin="5,1,0,0" 
									Grid.Column="1"
									HorizontalAlignment="Center" 
									VerticalAlignment="Center"
									Stroke="{TemplateBinding Foreground}" 
									Fill="{TemplateBinding Foreground}" 
									/>

								<Button x:Name="PART_DropDown"
									Background="{TemplateBinding Background}"
									BorderBrush="{TemplateBinding BorderBrush}"
									Foreground="{TemplateBinding Foreground}"
									VerticalAlignment="Stretch"
									Margin="0,-4,-4,-4"
									Style="{DynamicResource lunaHomesteadDropDownStyle}"
									HorizontalAlignment="Stretch"
									Grid.Column="1"
									Opacity="0">

									<Path Data="M0,0L3,3 6,0z" Margin="1,1,0,0" Grid.Column="1" Stroke="{TemplateBinding Foreground}" Fill="{TemplateBinding Foreground}" />
								</Button>
							</Grid>
						</luna:ButtonChrome>
					</Grid>
					<ControlTemplate.Triggers>
						<Trigger Property="Mode" Value="Dropdown">
							<Setter Property="Visibility" TargetName="PART_DropDown" Value="Collapsed"/>
						</Trigger>
						<Trigger Property="Mode" Value="Button">
							<Setter Property="Visibility" TargetName="PART_DropDown" Value="Collapsed"/>
							<Setter Property="Visibility" TargetName="path" Value="Collapsed"/>
							<Setter Property="Grid.ColumnSpan" TargetName="Bd" Value="2"/>
						</Trigger>
						<Trigger Property="IsMouseOver" SourceName="PART_DropDown" Value="true">
							<Setter Property="Opacity" TargetName="PART_DropDown" Value="1"/>
						</Trigger>
						<Trigger Property="IsEnabled" Value="false">
							<Setter Property="Foreground" Value="#ADADAD"/>
						</Trigger>
					</ControlTemplate.Triggers>
				</ControlTemplate>
			</Setter.Value>
		</Setter>
	</Style>
</ResourceDictionary>