HOWTO avoid flicker in full screen mode (i.e Gwenview)

[morgano]

In KDE, when desktop effects are enabled and an application use full screen, it sometimes flicker.
In my case i noted it using Gwenview, amd a second after it changed picture the whole screen flickered each time.

See here for workaround, and read above that post for explanation.
http://forum.kde.org/viewtopic.php?f=66&t=85772#p148190

Drawback: fullscreen apps may work slower.

Another method to do exacly the same:
https://fedoraproject.org/wiki/KDE/How_ ... en_flicker