When you create a custom theme using the Telerik approach, you have to make sure you have a resource dictionary for each Telerik assembly included in the project. For example, if you want to customize RadDocking control, you need to have a Themes folder containing a Telerik.Windows.Controls.xaml
resource dictionary, as well as Telerik.Windows.Controls.Navigation.xaml
resource dictionaries, even if some of them need to be left blank.
Please, check the attached screenshot for reference.
We will update the help article on that topic to include this note as soon as possible.
I hope this will help solve your issue.
the Telerik team
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