anchor.diff:  
     List get items => props['items'];
     String get selectorText => props['selectorText'];
  -  bool get fullSize => props['fullSize'];
     get _onChange => props['onChange'] != null ? props['onChange'] : _defaultOnChange;
  -
  -  num scrollStep;
  +  get _cssSelectorClass => props['className'] != null ? props['className'] : 'round-selector';
  +  get _showFirstLast => props['showFirstLast'];
  +
  +  get _visibleItemsWindowSize => ref('itemsDiv') != null ? ref('itemsDiv').marginEdge.width : null;
  +  get _spanWidth => ref('${items[0][VALUE]}') != null ? ref('${items[0][VALUE]}').marginEdge.width : null;
  +
     var browserWindow;
   
     static const String VALUE = 'value';
  
positive.code:     var _registeredComponent = registerComponent(() => new SelectorComponent(window));
      return (List items, DataReference selected,
          DataReference active, DataReference loading,
          {String key : 'selector', String selectorText : '', bool fullSize : true,
            onChange}) {
  
        return _registeredComponent({
  
negative.code:   }
  
    checkAndSetScrollStep(_){
  
      var _scrollListDiv = ref('round-list');
      var _scrollStep = _scrollListDiv.style.marginLeft;
  