Comment 17 for bug 1309744

Ok, so I think I've figured this one out.

The problem is that the /usr/bin/xdg-screensaver script does detect the desktop-environment (in our case: "xfce"), but when checking for it in "perform_action" there's actually no case that matches xfce, so it never does anything if it detects xfce.
This was previously not noted because we used xscreensaver, which has a special case built in.

There is one easy workaround: replace the '' in line 435 with 'xfce' and it should work.

The desired patch is probably adding a special case for light-locker just as there's one for xscreensaver and gnome-screensaver, cause it could also be used in other DEs.

However, there is one big caveat: the script in its current form always sets the screensaver timeout to the system default value of "600" (i.e. 10minutes). So the feature of remembering the timeout and re-setting it correctly on "resume" would have to be added in a second step.