anchor.diff:      //this.domElement.addEventListener( 'DOMMouseScroll', mousewheel, false ); // firefox
   
       keydownStream = window.onKeyDown.listen(keydown);
  -    window.onKeyUp.listen(keyup);
  +    keyupStream = window.onKeyUp.listen(keyup);
   
   
       handleResize();
  
positive.code:       }
  
      }
  }
  
negative.code: 
    StreamSubscription<MouseEvent> mouseMoveStream;
    StreamSubscription<MouseEvent> mouseUpStream;
    StreamSubscription<KeyboardEvent> keydownStream, keyupStream;
  
    EventEmitterEvent changeEvent;
  
  