If window decoration is modified within a short period of time, mutter
sometimes starts processing the second request before the first
UnmapNotify event has been received. In this situation, it considers
that the window is not mapped and does not expect another UnmapNotify /
MapNotify event sequence to happen.
This adds a separate counter to keep track of the pending reparents. The
input focus is then restored when MapNotify event is received iff all
the expected pending ReparentNotify events have been received.
Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
https://gitlab.gnome.org/GNOME/mutter/merge_requests/657
8f242f8bf0