I prepared a sample test project which contains the described setup and tested it both under IE7 and FF3 but unfortunately I was not able to reproduce the problem - the collapsing of the RadPane does not influence the movie.
Would you please examine the attached demo and modify it in order to reproduce the problem? If you succeed, please open a new support ticket and send it to me along with reproduction instructions and information about the used browser.
the Telerik team
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