This is bugging me. In past versions, KDE did not like my video card (NVidia Geforce4). I had to use a different window manager. Then in 4.4, to my delight, I was able to start using KDE again because it appeared that they had solved the problem with my card. Now I upgraded and I have the same problem again!!!!!!!!!!!!11

Here's my problem: When scrolling in KDE applications everything becomes blurred or there are sections of repeated parts. (See image of konquerer below). What was changed! I've checked my xorg and it appears okay. The effects advanced settings also seem to be the same. Any ideas before I file a bug report?

http://imagebin.org/110616

If you disable Desktop Effects does it occur? Are you using the latest version available of the NVIDIA driver?

I get that sometimes on my nvidia system too, with or without compositing.

I can't enable Desktop Effects after upgrading to 4.5 either, with an Nvidia FX5200 card. I'm using the propietary driver, which is limited to 173.x version, because this card is considered "legacy" by Nvidia.
I'll give the free nouveau driver a try...
(right now I can use effects via Xrender, but it's slow)

TheBlackCat wrote:I get that sometimes on my nvidia system too, with or without compositing.

For me it is always that way (or worse) for KDE apps. Some times I can run the mouse over it or scroll the bar one click at a time (ie slowly) to clear up the mess. But with some kde applications, there is nothing that I can do to make the scrolled window legible. Yet, if I run the same kde app in a different wm (ie openbox or e17 with compositing) everything works fine. That's why I'm sure that it is a KDE issue. (I just verified that it does it even if compositing is turned off.)