TreeListExpander.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
	<DrawingBrush x:Key="TreeListExpander" Stretch="Uniform">
		<DrawingBrush.Drawing>
			<DrawingGroup>
				<DrawingGroup.Children>
					<GeometryDrawing Brush="{DynamicResource UiElementForeground}" Geometry="F1 M 71.2133,42.6613L 113.652,85.4337L 71.3521,128.012L 61.3534,117.985L 93.3355,85.3087L 61.3395,52.7572L 71.2133,42.6613 Z "/>
				</DrawingGroup.Children>
			</DrawingGroup>
		</DrawingBrush.Drawing>
	</DrawingBrush>
</ResourceDictionary>