If the meta_window_actor_effect_completed() triggers inconsistent
accounting, there's also high chances that the thaw call will be
unexpected at this time too, which will lead to a g_error().
This makes mutter more lenient to effect_completed() calls of the
right type (i.e. those triggering freeze/thaw) being performed more
times than necessary in the upper parts. A warning will be issued,
but the process won't abort.
https://bugzilla.gnome.org/show_bug.cgi?id=777691
2cd78bffd9