Unfortunately I am not able to determine where the exact source of the issue is for your first problem. I will suggest you open a regular support ticket on this matter. Thus, we will do our best to find a quick solution for this abnormality.
In my attempt to replicate the erratic behavior I have created a test project with tab strip control and RadGrid. I have no luck in reproducing this problem. Please, if it is convenient for you, review the attached test web site and tell me if I am missing something.
the Telerik team
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