 import mx.resources.ResourceManager;
 
 import spark.components.supportClasses.NavigationStack;
+import spark.core.ContainerDestructionPolicy;
 import spark.components.supportClasses.ViewHistoryData;
 import spark.components.supportClasses.ViewNavigatorBase;
 import spark.effects.Animate;

    public function get length():int
    {
        return navigationStack.length;
    }
    
    //----------------------------------

        titleInvalidated =
        titleContentInvalidated =
        titleLayoutInvalidated = true;
        
        invalidateProperties();
    }
    
    /**
