May I ask you to isolate this issue in a project? You can open a new support ticket from your telerik.com account and send the project there.
Regards,
Martin Ivanov
Progress Telerik
Want to extend the target reach of your WPF applications, leveraging iOS, Android, and UWP? Try UI for Xamarin, a suite of polished and feature-rich components for the Xamarin framework, which allow you to write beautiful native mobile apps using a single shared C# codebase.