Using a StaticResource SolidColorBrush to define the Gradient Stop Colors
Ok, I found the problem: Using Color and not SolidColorBrush.. <Color x:Key=”colorbrushMedium”>#FF5A5A5A</Color> <Color x:Key=”colorbrushDark”>#FF222222</Color> <LinearGradientBrush> <GradientStop Color=”{StaticResource colorbrushMedium}”/> <GradientStop Color=”{StaticResource colorbrushDark}” Offset=”1″/> </LinearGradientBrush> This seems to solve my problem!