[gnome-shell] Avoid clobbering the root window event mask

[Owen Taylor <otaylor src gnome org>]

commit 432ad0f4512eb7456428a34951b38910a0676f45
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Fri May 1 18:35:55 2009 -0400

    Avoid clobbering the root window event mask
    
    Calling gdk_window_get_events() then gdk_window_set_events() will
    remove "exotic" X event masks that GDK doesn't know about like
    SubstructureRedirectMask. A window manager that doesn't select
    for SubstructureRedirectMask on the root window is no longer
    really a window manager, so various Bad Things were happening.
    
    We can just piggy-back on Mutter selecting for PropertyNotify
    events on the root window, so removing the code works fine.
    
    http://bugzilla.gnome.org/show_bug.cgi?id=580572 (reported by Mike Bursell)
---
 src/shell-global.c |   19 +++++++++----------
 1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/shell-global.c b/src/shell-global.c
index 0857e98..01ca0db 100644
--- a/src/shell-global.c
+++ b/src/shell-global.c
@@ -1170,7 +1170,6 @@ ClutterActor *
 shell_global_create_root_pixmap_actor (ShellGlobal *global)
 {
   GdkWindow *window;
-  GdkEventMask events;
   gboolean created_new_pixmap = FALSE;
   ClutterActor *clone;
 
@@ -1190,16 +1189,16 @@ shell_global_create_root_pixmap_actor (ShellGlobal *global)
       g_signal_connect (G_OBJECT (global->root_pixmap), "destroy",
                         G_CALLBACK (root_pixmap_destroy), global);
 
-      /* Watch the root window for changes. */
-      window = gdk_get_default_root_window ();
-      events = gdk_window_get_events (window);
-      events |= GDK_PROPERTY_CHANGE_MASK;
-      gdk_window_set_events (window, events);
-      /* Metacity handles some root window property updates in its global
-       * event filter, though not this one. For all root window property
-       * updates, the global filter returns GDK_FILTER_CONTINUE, so our
-       * window specific filter will be called.
+      /* Metacity handles changes to some root window properties in its global
+       * event filter, though not _XROOTPMAP_ID. For all root window property
+       * changes, the global filter returns GDK_FILTER_CONTINUE, so our
+       * window specific filter will be called after the global one.
+       *
+       * Because Metacity is already handling root window property updates,
+       * we don't have to worry about adding the PropertyChange mask to the
+       * root window to get PropertyNotify events.
        */
+      window = gdk_get_default_root_window ();
       gdk_window_add_filter (window, root_window_filter, global);
 
       update_root_window_pixmap (global);