I tried to replicate the issue which you described, but to no avail - you can take a look at the first grid from this demo
Please, let me know if there are any differences at your end, which I may be leaving out.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!