Alt+Tabbing into application windows is sometimes causing gnome-shell
to emit object:state-changed:focused events for an accessible with
the role of window. This is at least sometimes taking place after the
application window gains focus. Since no gnome-shell window seems to
be actually gaining focus, and since windows are expected to emit
window:activate events, these events appear safe to ignore. In addition,
failure to ignore them can cause Orca to load the gnome-shell script
incorrectly.