Refocus on application close is broken with focus stealing prevention

[tarek-y-ismail]

Related: #2586

Whenever a window is closed, it's expected that the window visually below it should become the one in focus. But at the moment with focus stealing prevention enabled, an incorrect surface (decoration?) is selected which cannot have focus. This requires the user to manually select the application they want via clicking (haven't tried alt+tab)

[AlanGriffiths]

I don't think focus stealing prevention is part of this. But as you don't provide a reproducer, it isn't clear whether this is the same thing:

1. run miral-app
2. Ctrl-Alt-T to start a terminal [gnome-terminal]
3. From terminal start kgx [kgx#1]
4. Ctrl-Shift-N for another kgx terminal [kgx#2]
5. Rearrange windows in order [kgx#2], [gnome-terminal], [kgx#1]
6. Close the top window [kgx#2]

Expect: [gnome-terminal] gets focus and order is [gnome-terminal], [kgx#1]
Actual: [kgx#1] gets focus and order is [kgx#1], [gnome-terminal]

[tarek-y-ismail]

Oh, sorry for leaving that out.

1. run miral-app with --focus-stealing="prevent"
2. Launch multiple terminals.
3. Close the focused (first) one via Ctrl+D

In mir on main, it will automatically focus the window underneath the one we just closed. In mir on control-new-window-placement-in-policies, focus is not properly set so you can't close all terminals by repeatedly pressing Ctrl+D.

Another scenario which might help pinpoint the issue:

1. run miral-app with --focus-stealing="prevent"
2. Launch multiple terminals.
3. Click on each terminal just to set focus
4. Click on the first one to focus it
5. Close it with Ctrl+D

You'll notice that the the last window focused before the one you just closed is now focused. If you close it, the window before it, and so on.