Great! > The problem is that you are using su to start a X/GNOME application as > root. su does not clear the environment, so XDG_RUNTIME_DIR points to > your users path, and the application running with root privileges > changes the permissions. > > Please stop using su (without -l) or running X apps as root.
Yes, that could have possibly be the reason. Perhaps I have started an X application from the root terminal. So it was me myself who caused that bug to appear. Will try not to do that anymore. Michael - thank you very much! Andreas