I am running 12.04 on three machines. On one of the machines I am running an Intel 82G33/G31 Express Integrated Graphics Controller as a display adapter. On this particular machine the grid of white dots overlaid on top of the wallpaper for the currently selected user is messed up big time.
Once I move the mouse, the graphics magically fix themselves. Then if I select a new user the grid of dots is messed up again until I move the mouse.
Once I log in the graphics seem to be running fine. Any ideas?