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.
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.