Alt+F4 is closing the Greeter's window
In 3.0 versions (at least in beta4) the Greeter’s window will get closed
by pressing Alt+F4. The user will be left with a blank, blue screen
(with the title bar at the top of the screen).
The keybinding Alt+F4 should be deactivated, if possible.
Feature Branch: bugfix/greeter-fixes-for-3.0,greeter:bugfix/12462-disable-alt-f4
Parent Task: #8230 (closed)