I'm not sure this is a bug. In Ubuntu 17.10 the login screen is ALWAYS running on VT #1, which you will reach with Ctrl+Alt+F1. That does not mean it's closed anything though. Try Ctrl+Alt+F2 to get back to your session (running on VT #2) with the programs still running.
** Changed in: gnome-shell (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1728474 Title: ctrl-alt-f1 closes all running programs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1728474/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs