[gtk/wip/chergert/quartz4u] macos: update viewable after changing focus

[Christian Hergert <chergert src gnome org>]

commit 70b698876a796925baa06e820885bf44db0e57b2
Author: Christian Hergert <chergert redhat com>
Date:   Wed May 6 18:05:13 2020 -0700

    macos: update viewable after changing focus
    
    This was done elsewhere, so cargo cult it

 gdk/macos/gdkmacossurface.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gdk/macos/gdkmacossurface.c b/gdk/macos/gdkmacossurface.c
index 92b430e8d9..870b9b2510 100644
--- a/gdk/macos/gdkmacossurface.c
+++ b/gdk/macos/gdkmacossurface.c
@@ -725,6 +725,8 @@ _gdk_macos_surface_set_is_key (GdkMacosSurface *self,
       else
         gdk_synthesize_surface_state (GDK_SURFACE (self), GDK_SURFACE_STATE_FOCUSED, 0);
 
+      _gdk_surface_update_viewable (GDK_SURFACE (self));
+
       event = gdk_focus_event_new (GDK_SURFACE (self), keyboard, NULL, is_key);
       _gdk_event_queue_append (GDK_DISPLAY (display), event);
     }