Created attachment 67405 [details]
kde-widget-closing-animation-flicker.mpeg

Version:           unspecified (using KDE 4.7.4) 
OS:                Linux

I don't know if this should be assigned to KWin or Plasma. Please reassign.

Bug:
Extender pop-ups (devices list, calendar emerging from clock widget, etc.) flicker when they are hidden.
Also panels behave in the same way when they are set to hide themselves.

Flickering appears in the last part of hiding, like 70%-90% of the pop-up width.
Pop-up becomes visible again at this position and is then hidden again.
Or this is how it looks like.

Video attached.

Reproducible: Always

Steps to Reproduce:
1) enable compositing
2) show a pop-up
3) hide it

Actual Results:  
Pop-ups flicker when hiding.

Expected Results:  
No flickering of hiding pop-ups.

I have checked that this behavior is NOT related to the Blur effect.