I'm sorry you are running into this problem. Since we've never seen this strange behavior before, it's hard to tell what is wrong. The best and fastest way for us to troubleshoot is to test locally. Would it be possible for you to send us your app? If it's not possible to share your full WPF app, then perhaps your developers can create a small demo that exhibits the same behavior. You can create a support ticket for that, which is confidential, unlike this forum thread.
the Telerik team
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