I am experimenting with Ubuntu 12.04 and have an ATI video card with an HD and DVI output. I connected two Samsung Syncmaster monitors and configured for dual heads using Catalyst. The monitor using the HD output has a desktop area that is not maximized....black edges around periphery. The monitor using the DVI output utilizes all of the monitor space (as it should). How can I configure the monitor using the HD output to maximize? Both are set at exactly the same resolutions in catalyst control center? I am not currently in front of my computer so I can give you more info later.