Richard Deeming is correct, you've used the
DynamicResource
to allocate the styles to the elements, but the styles themselves are using
StaticResource
to allocate the colours. You need to amend the styles themselves to use dynamic resources:
<Style x:Key="BaseStyle" TargetType="{x:Type Control}" >
<Setter Property="Background" Value="{DynamicResource FormBackground}" />
</Style>
A
StaticResource
is resolved and assigned when the style is loaded, and any changes to that resource won't be reflected. The
DynamicResource
uses an expression to resolve the value, so changes can be reflected.