Hello Wolfgang,

Thank you for the information and the attached project.

The reported behavior appears because the custom RadPane user controls are not based on the default RadPaneStyle. Basically, when using NoXaml dlls and creating a custom control deriving from UI for WPF control you will need to create a new style that is based on the default one. You can find some more information about this in the Styling the Controls help article (http://docs.telerik.com/devtools/wpf/styling-and-appearance/styling-apperance-styling-the-controls#styling-custom-controls).

In your case you will need to do this for each view that derives from RadPane. Here is an example for the OutputView class:

<Style TargetType="views:OutputView" BasedOn="{StaticResource RadPaneStyle}" />

You can add this line in the App.xaml resources after your merge the Telerik theme resources.

Regards,
Martin Ivanov
Technical Support Engineer