Fortunately, the old trick of disabling background draw did it for me too, and stopped the continuous malfunctions with OpenGL. But now, if I choose shaded mode for my views, only very few (if any) objects are shown shaded; most objects appear as something less than a wireframe: just a vague spray of dots, making it almost inmpossible to discern how objects are positioned relative to each other. Very frustrating, as arranging a scene becomes a bit of a trial and error process in this way. Wireframe mode works fine. Does this sound familiar to anyone, and is there a way to solve the problem?