[gtk/wip/chergert/quartz4u] macos: update stacking after hide

[Christian Hergert <chergert src gnome org>]

commit 0e1e2d633b95b74aef54f6ca2dc1608b42c18286
Author: Christian Hergert <chergert redhat com>
Date:   Mon May 4 15:25:08 2020 -0700

    macos: update stacking after hide

 gdk/macos/GdkMacosWindow.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gdk/macos/GdkMacosWindow.c b/gdk/macos/GdkMacosWindow.c
index 0de37529d9..3e1ac5be61 100644
--- a/gdk/macos/GdkMacosWindow.c
+++ b/gdk/macos/GdkMacosWindow.c
@@ -305,6 +305,8 @@
   inShowOrHide = NO;
 
   initialPositionKnown = NO;
+
+  [self invalidateStacking];
 }
 
 -(BOOL)trackManualMove