As I explained in your support ticket, this behavior is the default browser behavior of IE10 and not Telerik specific. Try opening the demo in other browsers and you will confirm the difference.
Hope this helps.
All the best,
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed