I'm having the same annoyance on edgy, it happens when running KDE applications like amarok. In the desktop file for HTTP Cache Cleaner (/usr/share/services/http_cache_cleaner.desktop) there is a line "X-KDE- StartupNotify=false" which probably avoids that the program appears in the window list in KDE but it doesn't seem to work in Gnome.
-- Launching HTTP Cache Cleaner https://launchpad.net/bugs/60315 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
