I had the issue described above, and decided to give the nouveau driver a try instead of the proprietary nvidia driver I had been using. I cleared out all graphics card and monitor related sections from xorg.conf file and replaced simply with
Section "Device" Identifier "nvidia card" Driver "nouveau" Option "GLXBlank" "true" EndSection then launched in gnome-control-center and arranged the monitors next to one another. Now the lock screen dialog always shows up on the monitor the mouse was last set. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/848562 Title: gnome-shell lock screen does not display password prompt To manage notifications about this bug go to: https://bugs.launchpad.net/gnome-screensaver/+bug/848562/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs