I am not aware of this problem and I am unable to reproduce it on my end.
To be able to help you I will need to reproduce the issue locally. Is it possible to provide a live URL to the problematic page or a sample working project which demonstrates the problem?
You have also not answered my questions in my earlier reply. Are you able to reproduce the problem with the latest version of the control Q2 2011 SP1?
Does the problem happen in the live demos
Have you customized the external built-in dialogs?
All the best,
the Telerik team
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