GNOME Bugzilla – Bug 668876
Lock dialog appears only on one monitor when using multiple monitors
Last modified: 2014-08-19 20:43:19 UTC
This happened after upgrade from 3.0 to 3.2. It makes everything on the monitor visible even when system is locked - one major setback when you lock your system and move away from your system.
gnome-screensaver is obsolete, and this particular bug has been fixed in gnome-shell itself, with the lock screen covering all the screens, and the password entry being on the primary monitor.