anchor.diff:        }
       });
   
  -
  -    querySelector(spaceCenter).onMouseOver.listen((mouseEvent) {
  -      var menu = querySelector(spaceMenu);
  -      if ( menu.style.zIndex == "99" ){
  -        menu.style.zIndex = "102" ;
  -        menu.classes.add("open") ;
  -      }
  -    });
  -    
  -    querySelector(spaceMenu).onMouseLeave.listen((mouseEvent) {
  -      var menu = querySelector(spaceMenu);
  -      if ( menu.style.zIndex != "99" ){
  -        menu.style.zIndex = "99" ;
  -        menu.classes.remove("open") ;
  -      }
  -    });
  -    
  -    
  -  }
  +  }
  +  
  +  void _toggleMenu(){
  +    var menu = querySelector(spaceMenu);
  +    if ( menu.style.zIndex == "99" ){
  +      menu.style.zIndex = "102" ;
  +      menu.classes.add("open") ;
  +    }else{
  +      menu.style.zIndex = "99" ;
  +      menu.classes.remove("open") ;
  +    }
  +  }
  +  
     
     void _moveCenter(Point start, Point end){
       double centerRightComputed =   -end.x + start.x  + centerRight ;
  
positive.code:     
      
      querySelector(spaceMenu)
      ..style.zIndex = "99"
      ..style.position = 'absolute'
      ..style.right = (centerRight  - centerSize /2 +2   ).toString() + "px"
      ..style.top =  centerTop < window.innerHeight/2  ? (centerTop+1  + centerSize /6 ).toString()+ "px" : (centerTop+1  - centerSize *8/6 ).toString()+ "px"
  
negative.code:     querySelector(spaceCenter).onMouseDown.listen((mouseEvent) {
        _startMovingCenterPosition = mouseEvent ;
        _movingCenter = true ;
        _toggleMenu();
        querySelector(spaceCenter + " a img").attributes["src"] = "assets/img/compass_275_red.png";
      });
  
  