anchor.diff:      _loadingOverlay.addChild(_overlaySpinner);
     }  
   
  -  void _configureZones() {
  +  void _configureAutoScroll() {
       Ranger.Application app = Ranger.Application.instance;
   
       Ranger.Size size = contentSize;
       double minS = min(size.width, size.height) / 2.0;
       centerZoneRadius = minS - (minS * 0.5);
   
  +//    autoScroll = new TweenAutoScroll.withRadius(centerZoneRadius);
       autoScroll = new SpongyAutoScroll.withRadius(centerZoneRadius);
   //    autoScroll = new TightAutoScroll.withRadius(centerZoneRadius);
       addChild(autoScroll.node, 12, 930);
     }
   
  +  set autoScrollEnabled(bool b) => autoScroll.autoScrollEnabled = b;
  +  bool get autoScrollEnabled => autoScroll.autoScrollEnabled;
  +  
     void toggleScrollZoneVisibility() {
       autoScroll.zone.iconsVisible = !autoScroll.zone.iconsVisible;
       
  
positive.code:   double centerZoneRadius = 0.0;  // computed below
  
    StreamSubscription _centerZoneSubscription;
    bool autoScrollEnabled = true;
    
    Vector2 shipHudPosition = new Vector2.zero();
    Vector2 zoneEdgePosition = new Vector2.zero();
  
negative.code: 
      _configOverlay();
  
      _configureAutoScroll();
      
      scheduleUpdate();
    }
  