I think its all tied to this post WindowManager.Update calling BrowseClass.UpdateViewRecord - RC = ErrorCode() - Error 78 Invalid Number of Parameters
If I click on one of the column headers as I have column header sorting enabled, the up and down and page up and page down buttons work.
Its on a key with two elements which total 2052 bytes in length, so by clicking on the column header is removing the key from the equation.