I created a test application with a treeview using implicit themes with the XAML files loaded into project. That works fine. If I move the treeview into a usercontrol in a separate project, it does not work. I tried both methods from here with no success:
https://blogs.msdn.microsoft.com/wpfsdk/2007/06/08/defining-and-using-shared-resources-in-a-custom-control-library/
It fails when loading Telerik.Windows.Controls.Navigation.xaml. It doesn't have a problem loading Telerik.Windows.Controls.xaml. The sample in the link
As a side note, I am doing the same thing with the map control and don't have any issues with it.
Link to the Project:
https://file.ac/1GnUz6lTPqM/
Here's the snippet from the UserControl:
<
UserControl.Resources
>
<
ResourceDictionary
>
<
ResourceDictionary.MergedDictionaries
>
<
ResourceDictionary
Source
=
"Themes/System.Windows.xaml"
/>
<
ResourceDictionary
Source
=
"Themes/Telerik.Windows.Controls.xaml"
/>
<
ResourceDictionary
Source
=
"Themes/Telerik.Windows.Controls.Navigation.xaml"
/>
</
ResourceDictionary.MergedDictionaries
>
</
ResourceDictionary
>
</
UserControl.Resources
>