Good 1 April joke! 2009.
I faced the same problem with 2010.2.826.35.
Consider the markup:
handler is never called.
The POST request is executed on "Page size" RadComboBox change,
OnLoad and other page methods are executed but not that one.
NeedDataSource is called initially and on prev, next, page button clicks.
So if the page size feature is not working, how to hide it?
Besides the NextPrevAndNumeric
mode name is wrong since it must display only Next, Prev and page buttons, but no page size!