Actually, if your question concerns the TimePicker
control, this is a known bug and the fix will be shipped with the next release due in a week. I could not reproduce similar bug with the calendar. If you have problems with it, it would be very useful if you send a sample project illustrating this matter, so that we can reproduce the problem locally and try to resolve it. You can zip the files and attach them to a new support thread.
All the best,
the Telerik team