Rebooting did not fix this issue; reseating the cable allowed X Server Settings to detect the monitor. So apparently a loose monitor cable can put the display into a limbo state.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1234334 Title: windows on previously disconnected second monitor no longer responsive To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1234334/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
