Comment # 12 on bug 73625 from Dieter Nützel

Now I get partially some color squares:

Glamor (glamor-0.5.1-39.14)
KDE 4.12.1
kwin
GL desktop effects ON
UVD/video window on all virtual desktops (sticky)

scroll with mouse wheel through all (4 virtual desktops) GL cube

Sometimes some redraws show partially color squares, as long as I gave the
system time for full refresh...

=> system is on its limits?! 

Or glamor is in the way or need optimization.