I have created a sample RadGrid web site using the provided code. On my side everything works as expected. Please find the attached application and try to determine the crucial differences between our projects which may cause the issue.
Furthermore, please ensure that the CommandItemTemplate and scrolling are configured properly.
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 now.