Could you please test the latest internal build of RadEditor for ASP.NET AJAX
( Telerik.Web.UI_2009_1_514_trial_hotfix.zip) and see whether the problem still persists?
If the problem is not fixed, please open a support ticket and send a sample working project that demonstrates the problem along with steps to reproduce and sample content for test. Once we are able to reproduce the problem, we will do our best to help.
the Telerik team