Same issue after upgrading to 15.04. Solved this by uninstalling gnome-screensaver.
Contrary to comment #63 this completely solved the issue for me. I have the ubuntu lock screen only once as expected.
Same issue after upgrading to 15.04. Solved this by uninstalling gnome-screensaver.
Contrary to comment #63 this completely solved the issue for me. I have the ubuntu lock screen only once as expected.