I am using Suse 11.1 64-bit version with kde and dual head. “Xinerama” with different screen resolutions : right monitor 1024X768 (main screen), left monitor 1280x1024.
I have no problem on the right screen, but if I click on the maximize window button (or double click of the window) of an application on the left screen, the window expand to the maximum horizontal but stops vertical on the height of the right screens control bar. There is also a small border of the control bar on my left screen 
However if I click on the video in kdetv or on the visualization effects of kaffeine the whole screen is used (is not a window mode)…