I've also had this issue and do not have auto-login enabled, it might be worth nothing that the upper panel from my second monitor has disappeared both times this has happened.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1799293 Title: gnome session: Must ask twice to lock the screen Status in gnome-shell package in Ubuntu: Confirmed Status in gnome-shell-extension-dashtodock package in Ubuntu: Confirmed Bug description: 1) Ubuntu 18.10 (new install) 2) gdm3 3.30.1-1ubuntu5 Preconditions The session's user has auto-login enabled (i.e. the system starts and the user is not prompted for a password but directly presented with the desktop) 3) What should happen: Unlocked desktop is showing. Lock screen is invoked (via WIN+L or via top right corner menu) and the lock screen is engaged (that is, lock screen clock shade drops down and screen fades to dark). Pressing ENTER brings back the lock screen and the password is prompted. 4) What happens: First Win + L lets the system in a half locked state in which the contents of the desktop are seen although no interaction is possible. A second Win + L correctly invokes the lock screen. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1799293/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
