[gnome-shell] popupMenu: Fix another child popup regression

[Jasper St. Pierre <jstpierre src gnome org>]

commit 6fd5f0e3de7a51d7b64e1f90772cbdcf2d361699
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Mar 14 11:51:10 2013 -0400

    popupMenu: Fix another child popup regression
    
    When switching menus, we need to make sure we close all existing
    grabs, not just the first one.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=695859

 js/ui/popupMenu.js |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/js/ui/popupMenu.js b/js/ui/popupMenu.js
index 3d2b4e6..b751daf 100644
--- a/js/ui/popupMenu.js
+++ b/js/ui/popupMenu.js
@@ -2110,9 +2110,9 @@ const PopupMenuManager = new Lang.Class({
     },
 
     get activeMenu() {
-        let actor = this._grabHelper.currentGrab.actor;
-        if (actor)
-            return actor._delegate;
+        let firstGrab = this._grabHelper.grabStack[0];
+        if (firstGrab)
+            return firstGrab.actor._delegate;
         else
             return null;
     },