We tried to reproduce the reported issue on our side, but to no avail. Please find attached a sample web application that shows the proper work as of the control.
If the problem persists, I think it will be best if you can open a support ticket and send us a simple running project (incl. CSS, images, skins, DB backup if needed and so on) demonstrating the problem (and step-by-step instructions on doing so). In that way we can reproduce and pinpoint the problems you're facing on our side, understand the logic of your application and provide a solution.
the Telerik team