[metacity] display: create MetaWindow on MapNotify event

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 072f8eb2027606091756933f84f1296cf26b6508
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Mar 5 01:34:35 2017 +0200

    display: create MetaWindow on MapNotify event

 src/core/display.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/src/core/display.c b/src/core/display.c
index ae56542..047f338 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -2282,6 +2282,15 @@ event_callback (XEvent   *event,
         }
       break;
     case MapNotify:
+      /* NB: override redirect windows wont cause a map request so we
+       * watch out for map notifies against any root windows too if a
+       * compositor is enabled:
+       */
+      if (window == NULL && event->xmap.event == screen->xroot)
+        {
+          window = meta_window_new (display, event->xmap.window, FALSE,
+                                    META_EFFECT_TYPE_CREATE);
+        }
       break;
     case MapRequest:
       if (window == NULL)