The message tray focus grabbing code sets the stage input
mode to Shell.StageInputMode.FOCUSED when the overview is
not visible. This ensures the stage window's input
region gets reshaped to include the notification chrome,
and so that input events get delivered appropriately to
the notification that grabbed focus.
The message tray code never tries to restore the stage input
mode later. Instead, the code relies on the stage input
mode (and input region) getting reset to
shell.StageInputMode.NORMAL automatically when focus moves
back from the shell chrome to a window in the user's session.
It's not really correct to set the stage input mode based
on the overview's visibility, though. At the login screen,
even though no overview is visible, the stage input mode is
Shell.StageInputMode.FULLSCREEN which is sufficient
for the notification's needs, Furthermore,
Shell.StageInputMode.FOCUSED is insufficient for the login
dialog's needs since the login dialog isn't considered
part of the shell's chrome and won't get included in the
stage input region.
This commit changes the message tray code to only set the
stage input mode if the current stage input mode isn't good enough,
rather than assuming the input mode isn't good enough just because
the overview is hidden.
https://bugzilla.gnome.org/show_bug.cgi?id=660919
12e3921f81