Version: (using KDE 4.2.2) Installed from: Ubuntu Packages While compositing basically works fine (well, it could be faster ... ;) I get black windows when I reach a certain number of opened windows. It must be something around 14 opened windows at the same time, up to which everything is fine. After that new windows appear entirely black with just the shadow. The 14 others stay fine, though. When I close some of the 14 good windows and trigger repaints of some of the black windows those get painted fine now. So there seems to be some limit of concurrently displayable windows. Card is an Nvidia GeForce3 Ti 200, AGP. Using the binary driver version 96.43.10 (the best possible for this card). System is Kubuntu Jaunty Jackalope: KDE 4.2.2 Xorg 7.4 Xserver 1.6 Kernel 2.6.28-11-generic
Oh, and it happens only with OpenGL compositing, not with XRender.
Sorry to say but that is a really old NVIDIA bug. I used to have it with Compiz in the time when the 96.xx driver was the most recent version. As I don't think NVIDIA will fix in that old driver versions it's really sad :-(
afair it helped to /NOT/ use blurring (delays by less TRAM consume) or direct rendering (though latter won't exactly improve performance...), i.e. indirect should more or less fix this by the cost of a performance hit. (unfortunately old drivers didn't support Xrender XForm as well..)
Hmm, for blurring you need shaders, right? So I can't use blurring anyway. And deactivating direct rendering didn't help. It just became even slower. So, as I won't count an Nvidia fixing it, it seems I'll need a new graphics card... :(