     //----------------------------------
     //  parentNavigator
     //----------------------------------
+    private var _parentNavigator:ViewNavigatorBase;
+    
     /**
      *  The parent navigator for this navigator.
      * 

     *  @playerversion AIR 2.5
     *  @productversion Flex 4.5
     */
    public var parentNavigator:ViewNavigatorBase;
    
    //----------------------------------
    //  transitionsEnabled

    protected var _navigationStack:NavigationStack;
    
    /**
     *  @private
     *  The navigation stack that is being managed by the navigator.
     *  An empty navigation stack is automatically created when
     *  a navigator is created.
     * 
     *  @default null
     */ 
    mx_internal function get navigationStack():NavigationStack
    {
        return _navigationStack;
    }
    
    /**
     *  @private
     */ 
    mx_internal function set navigationStack(value:NavigationStack):void
    {
        if (value == null)
            _navigationStack = new NavigationStack();
