Hello Falk Wegener,
We're still researching the cause for the issue. A sample application would be of a great help. Most probably, the issue is related to disposing the grid and its elements in specific cases with a user control or panels which are not visible and contain RadGridView
However we're not absolutely sure and are still working on this issue. If you send us a sample application, it will help us to fix it sooner.
Also, I would suggest to try to workaround this issue by calling the Dispose
method of RadGridView
when the form that contains the grid is closed (disposed).
Please try this and tell us if this solves the problem.
the Telerik team