 import spark.components.supportClasses.ViewNavigatorBase;
 import spark.events.ElementExistenceEvent;
 import spark.events.PopUpEvent;
+import spark.transitions.ViewTransitionBase;
 
 use namespace mx_internal;
 

            return;
        
        lastAspectRatio = aspectRatio;
        
        if (autoHideFirstViewNavigator)
        {

        if (!viewNavigatorPopUp|| !viewNavigatorPopUp.isOpen)
            return;
        
        // Since view transitions can temporarily alter the display tree, we
        // need to end all view transitions so that the display tree is restored
        // to a correct state.
        ViewTransitionBase.endTransitions();
        
        viewNavigatorPopUp.addEventListener(PopUpEvent.CLOSE, navigatorPopUp_closeHandler);
        viewNavigatorPopUp.close(true);
        viewNavigatorPopUp.removeEventListener('mouseDownOutside', navigatorPopUp_mouseDownOutsideHandler);
