anchor.diff:  
   void _updateAbout() {
     var popDisplay = targetPlatform.showAbout ? 'inline-block' : 'none';
  -  querySelector('#popup').style.display = popDisplay;
  +  html.querySelector('#popup').style.display = popDisplay;
   }
  
positive.code: library pop_pop_win;
  
  import 'dart:async';
  import 'dart:html';
  
  import 'package:stagexl/stagexl.dart' hide KeyboardEvent;
  
  
negative.code:     ..backgroundColor = 0xb4ad7f
      ..transparent = true;
  
    var stage = new Stage(html.querySelector('#gameCanvas'), options: options);
  
    new RenderLoop()..addStage(stage);
  
  