Comment 27 for bug 1054299

Oh, found xfpm_lock_screen :) And gnome-screensaver is not alone :) The other locking methods are used in case xfce4-power-manager is installed without xfce4-session. If gnome-screensaver is kept in the list, I would suggest it is tried as the last option, since if it is installed, it will start even if its daemon is not running and even if xscreensaver's daemon is running.