Bug 1905000

Same as https://bugzilla.redhat.com/show_bug.cgi?id=1904371 for RHEL 7.9

Description of problem:
  - once password is entered into lock screen, the menu bar appears, but the lock screen image persists
  - when clicking menu items after this, the sub menus do not disappear if the mouse is moved out of them and they persist (see screenshots)

Version-Release number of selected component (if applicable):


How reproducible:
  - OS:     RHEL 7.9
  - kernel: 3.10.0-1160.2.2.el7.x86_64
  - window manager: X11
  - gnome-shell: 3.28.3-30.el7.x86_64 ( gnome classic!)
  - mutter: 3.28.3-26.el7.x86_64


Steps to Reproduce:
  1. start with a clean desktop
  2. start a terminal and running "top"
  3. Press WINDOWS key, so the "Windows Picker" is active.
  4. Wait for the screensaver (you can set the interval to 1 minutes so you do not have to wait for too long)
  5. The screen fades away (wait a bit more until complete blank, e.g. 30 seconds); when you interrupt to early the lock screen it not yet active
     and you go straight to desktop
  6. When it is completely black, click the mouse or hit some key
  7. the lock screen appears
  8. press ESC (or push upwards with mouse)
    (Note again: I disabled password; but according to user report the problem also triggers when you enter password)
  9. Problem reproduces: half-login; animation caught half-way, top-bar half-working
 10. Try Alt-F2 r: then normal desktop will appear (but it does not show the window picker; else it would have been to easy...)

Actual results:
  - password screen persists
  - menu windows overlap and perssist

Expected results:
  - password screen vanishes
  - regular background appeares
  - menu and submenu only persist as long as the mouse is hovering on it