To avoid duplicate posts, we will continue our communication in the other support ticket post that you have opened on the matter.
In version 2009.1 402 dropdown list for the page size puts scroll bars causing the page numbers (i.e. 10, 20, 50) to wrap vertically on each other. In order to avoid this erroneous behavior, please upgrade to latest version of RadControls for ASP.NET.AJAX.
the Telerik team