Fix for RibbonBar on XP

[Antonio Linares]

This change is required three times in Class TRBtn (Buttons for the RibbonBar) to properly show the popup menus on XP:

Code: Select all  Expand view

      ::oPopup:Activate( ::nTop + ::nHeight(), ::nLeft - oWnd:nLeft, oWnd, .f. )
 

On Windows 7 it was working fine but failed on XP. Now it is ok