Version: (using Devel) Installed from: Compiled sources OS: Linux I guess I experience this bug because I have a slower machine (P4 2.6, GeForce FX 5600) So, in order to reproduce, try putting your cores under heavy load. How to reproduce: 0) enable taskbar thumbnails 1) hover any taskbar app until the thumbnail shows up 2) click on it in order to iconify the window 3) let the popup be painted now be prepared: the next step must be done as fast as you can 4) click on the taskbar app again and, while the window shows, quickly move the mouse away from the taskbar I often need to do it server times before I am able to reproduce. The taskbar popup remains on the screen until you hover the taskbar again.
Created attachment 23948 [details] example screencast
No more taskbar popups around :-)