[gtk+] window: add note about window references

[Matthias Clasen <matthiasc src gnome org>]

commit 26b4fc65b92a462beb8020097d2e87d0936ce804
Author: David Schleef <ds schleef org>
Date:   Sat Dec 10 14:29:16 2011 -0800

    window: add note about window references
    
    https://bugzilla.gnome.org/show_bug.cgi?id=665928

 gtk/gtkwindow.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 3d9e858..303d319 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -1837,6 +1837,14 @@ gtk_window_buildable_custom_finished (GtkBuildable  *buildable,
  *
  * If you simply want an undecorated window (no window borders), use
  * gtk_window_set_decorated(), don't use #GTK_WINDOW_POPUP.
+ *
+ * All top-level windows created by gtk_window_new() are stored in
+ * an internal top-level window list.  This list can be obtained from
+ * gtk_window_list_toplevels().  Due to Gtk+ keeping a reference to
+ * the window internally, gtk_window_new() does not return a reference
+ * to the caller.
+ *
+ * To delete a #GtkWindow, call gtk_window_destroy().
  * 
  * Return value: a new #GtkWindow.
  **/