Can you please verify that you are using the latest version 2008.1.619 of RadControls for ASP.NET AJAX in your project? You may also test the solution with the Beta version of the new release (Q2 2008 Futures
) to see whether this makes a difference. Additionally, test whether moving the grid instance outside of the tab control alleviates the abnormality.
If the problem persists, I will appreciate if you assemble a stripped working version of your project and send it enclosed to a formal support ticket. I will familiarize with your complete code logic and will get back to you with more info on the subject.
the Telerik team