Version: 3.5.5 (using KDE KDE 3.5.5)
Installed from: Ubuntu Packages
Each time a new window is created (or some other undetermined situations), kwin enters in focus-in/focus-out race (> 10 events/sec.), either on one single window or with some others in the same workspace. It makes KDE unusable since each mouse clic may take several seconds to be handled (if ever...). Draging the window, holding a mouse button down for 5-10 seconds or changing workspace (sometimes) stops this behavior until another event triggers the problem again. The problem occurs on two different systems (one laptop and one desktop), which allows to rule-out a graphics card problem. The problem appeared when I installed KDE 3.5.5 on these two systems.
Happens here, too, since I updated to KDE 3.5.5 (SUSE 10.1 RPMs). Seems to be related with the "Focus follows Mouse" policy. Changing the policy to "Foucs on Click" has helped. Using KDE 3.5.5 with a "Focus follows Mouse" policy is almost impossible.
*** This bug has been marked as a duplicate of 135250 ***