anchor.diff:      _nodeLabel.style..marginAfter = "0px"
           ..marginBefore = "0px";
       _nodeLabel.text = this._model.title;
  -    _nodeLabel.style.height = "${labelHeight}";
  +    _nodeLabel.style.height = "${_labelHeight}";
       if (_model.isLeaf()) {
         _createLeafNode();
       } else {
  
positive.code:   static const String VERTICAL_ORIENTATION = "none";
    static const String HORIZONTAL_ORIENTATION = "left";
    final List<ViewNode> _children = new List();
    String _orientation = VERTICAL_ORIENTATION;
    DataModel _model;
    DivElement _container;
    DivElement _content;
    ParagraphElement _nodeLabel;
    final int labelHeight = 19;
    final int padding = 3;
  
    ViewNode(this._model, num width, num height, [this._orientation]) {
      assert(this._model != null);
  
negative.code:   
    DataModel get model => this._model;
    
    ViewNode get parent => this._parent;
    
  }
  