[gtk+/combo-refactor] Fixed GtkComboBox to properly set tearoff state on delegate GtkTreeMenu.

[Tristan Van Berkom <tvb src gnome org>]

commit 293fc6c1481af68a55f6b94e917337eb9478fca2
Author: Tristan Van Berkom <tristan van berkom gmail com>
Date:   Thu Dec 30 16:46:50 2010 +0900

    Fixed GtkComboBox to properly set tearoff state on delegate GtkTreeMenu.
    
    This breakage was also the cause of not correctly positioning the child
    menu over the selected item.

 gtk/gtkcombobox.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index 84678a3..f42a14f 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -4799,6 +4799,11 @@ gtk_combo_box_set_add_tearoffs (GtkComboBox *combo_box,
     {
       combo_box->priv->add_tearoffs = add_tearoffs;
       gtk_combo_box_check_appearance (combo_box);
+
+      if (GTK_IS_TREE_MENU (combo_box->priv->popup_widget))
+	_gtk_tree_menu_set_tearoff (GTK_TREE_MENU (combo_box->priv->popup_widget), 
+				    combo_box->priv->add_tearoffs);
+
       g_object_notify (G_OBJECT (combo_box), "add-tearoffs");
     }
 }