Version:           unspecified (using KDE 4.5.1) 
OS:                Linux

Installed kde by launchpad/kubuntu-backports lucid lynx (10.04): package kubuntu-desktop

kwin --version:
Qt: 4.7.0
KDE Development Platform: 4.5.1 (KDE 4.5.1)
KWin: 4.5.1 (KDE 4.5.1)

Since I've upgraded to KDE 4.5

the thumbnails shown when hovering over the taskbar are way too bright resulting most of the time in bare white thumbnails 

(Desktop Effects/Taskbar Thumbnails). 

Same happens at 

Desktop Effects/Present Window 

(when I zoom out to see all my windows)

Reproducible: Always

Steps to Reproduce:
Just activate the effects at System Settings/Desktop Effects/All Effects

Actual Results:  
the thumbnails shown when hovering over the taskbar are way too bright resulting most of the time in bare white thumbnails 

Same happens at 

Desktop Effects/Present Window 

(when I zoom out to see all my windows)

Expected Results:  
Same as before upgrading: The thumbnails actually serve to recognise the windows, showing a "correct" thumbnails

Installed kde by launchpad/kubuntu-backports lucid lynx (10.04): package kubuntu-desktop