I updated the Kernel and nVidia Drivers (GForce 6150 from the nVidia repo) via YaST. On my KDE desktop, after restarting, Firefox, Thunderbird, Chromium and Konqueror show a titlebar, but the window content is all black, I can right click and get the context menus and click and get the dropdowns, so they are running; I just can’t see the contents.
This also occurs with new instances of Dolphin, but the two Dolphin windows present on startup from my previous session are fine.
I’m having to post this from my XP laptop-Oh the SHAME… :’(
It’s a video driver issue-I removed the packaged drivers, and installed 270.41.06 manually and had the same problem, but backing off to 260.19.63, which I happened to have, fixed it…
On userbase.kde.org I found that this problem can occur if composite is activated with openGL or compiz. In KDE4 you can switch composite effects off/on with Alt-Shift-F12, which helped me. Look at the link for more information.
In my case (openSUSE 11.4 x86-64 and NVIDIA 270.42.19) Alt-Shift-F12 has no effect. However switching composite effects off in System Settings gets the window back to normal. After that if I switch composite back to on the window remain OK, however opening a new window it comes up black. By using the mouse to make the black window smaller, it becomes normal but becomes black again if it is enlarged.