anchor.diff:  
   
   
  -
  -
  -
  -
  
positive.code: 
  
  class ListPicker extends Component {
  
    Skin listSkin;
    Skin buttonSkin;
  
negative.code: 
    List _data;
  
    ListPicker({this.listSkin, this.buttonSkin}) : super() {
      button = new Button();
      list = new PopupList();
    }
  
    void set data(List val) {
      _data = val;
  