Could you please open a support ticket on the matter? If it is possible, it would be very helpful if you could isolate the troubled behavior in a sample project and send it over via a support ticket. This way we will be able to troubleshoot the problem locally and provide you with a solution for it if possible.
All the best,
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed