When dragging a window with enabled OpenGL compositing to the top edge of the screen to maximize it or to the sides to spread it over half or a quarter of the screen a fully opaque box is shown which is either completely white or completely black.
Steps to Reproduce:
Drag the window to the top, right or left edge of the screen to trigger maximization.
A black or white box is shown indicating which part of the screen the window would fill hiding everything that's below.
The box that appears should be white (it's sometimes black) and semi-transparent instead of opaque as it was in KDE 4.8.3.
Only happens when OpenGL compositing is enabled, works fine with Xrender.
Using Nouveau driver from Kernel 3.3.0.
depends on the graphicssystem
*** This bug has been marked as a duplicate of bug 301068 ***