We can confirm that this is a bug in the control and this is why it is already logged in our PITS. You can rise its priority by giving your vote for it here
. Also, in our PITS, you can track the status of this issue. Please vote for this item as your vote will help us to understand the impact of this behavior.
Please accept our apologize for the inconvenience caused. Thank you for understanding.
Pavel R. Pavlov
the Telerik team