[gtk+] docs: Copy GtkSizeGroup ownership discussion to GtkWindowGroup

[Matthias Clasen <matthiasc src gnome org>]

commit d3f1312c98db6c5994e6aee8223913fa9f361af8
Author: Evan Martin <martine danga com>
Date:   Fri Nov 12 10:43:20 2010 -0800

    docs: Copy GtkSizeGroup ownership discussion to GtkWindowGroup
    
    The two behave identically, so the text is the same with s/size/window/.

 docs/reference/gtk/tmpl/gtkwindowgroup.sgml |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gtk/tmpl/gtkwindowgroup.sgml b/docs/reference/gtk/tmpl/gtkwindowgroup.sgml
index 71bd142..9336814 100644
--- a/docs/reference/gtk/tmpl/gtkwindowgroup.sgml
+++ b/docs/reference/gtk/tmpl/gtkwindowgroup.sgml
@@ -6,7 +6,13 @@ Limit the effect of grabs
 
 <!-- ##### SECTION Long_Description ##### -->
 <para>
-
+#GtkWindowGroup objects are referenced by each window in the group,
+so once you have added all windows to a #GtkWindowGroup, you can drop
+the initial reference to the window group with g_object_unref(). If the
+windows in the window group are subsequently destroyed, then they will
+be removed from the window group and drop their references on the window
+group; when all window have been removed, the window group will be
+freed.
 </para>
 
 <!-- ##### SECTION See_Also ##### -->