Version: 4.8.0 (using KDE 4.8.0)
When there are two windows that are overlapping and I klick on the inactive one so it gets activated and rised, before the slide back effect starts, it will pop to the front, overlapping the previously active window for approx. one frame and then lower back to its original bottom position. After that the slide back effect will start.
It seems that the window texture is also distorted in the overlapping area when the problem occurs.
This is some kind of bug which makes KDE appear "Somewhat choppy" without really recognizing what's there.
Steps to Reproduce:
Activate the slide back effect.
Open two windows and drag them so that they are overlapping.
click on them many times so that the focus changes many times and look closely.
Sometimes you will see the inactive window be raised for one frame before the other one slides back. But this doesn't happen often.
Proper sliding back effect.
Appears on Nvidia as well as Intel graphics on different machines. ATI not tested.
Shortly tested it with Xrender and this shows the Issue, too and even more obvious
While testing this Bug
Raising MaxFPS or something other made the problem appear very often.
I can reproduce and I think it is caused by the fact that the stacking order is changed before the animation starts. So you have one frame with the new stacking order before the animation kicks in.
*** Bug 304479 has been marked as a duplicate of this bug. ***
Git commit 4f77dbf90185bf2683a5b19da7d1b8b35c012520 by Thomas Lübking.
Committed on 30/01/2013 at 21:50.
Pushed by luebking into branch 'master'.
re-settle slideBack effect to stackingOrderChanged
M +44 -76 kwin/effects/slideback/slideback.cpp
M +5 -7 kwin/effects/slideback/slideback.h