Graeme, As gqview works fine with my ATI in MergedFB mode (for example, I can choose the screen for fullscreen), I've looked in the gtk code to see how they handle Xinerama. I'm not a X11 guru, so I don't understand how it really works, but I found interesting things in the code. All seems to be in dir: .../gtk+-x.y.z/gdk/x11/ of the source, and especially in the file: .../gtk+-x.y.z/gdk/x11/gdkscreen-x11.c Hope it helps. -- Frédéric http://www.gbiloba.org