anchor.diff:  library pop_pop_win;
   
   import 'dart:async';
  -import 'dart:html';
  +import 'dart:html' as html;
   
   import 'package:stagexl/stagexl.dart' hide KeyboardEvent;
   
  
positive.code:   new GameRoot(size, size, m, stage, resourceManager);
  
    // disable touch events
    window.onTouchMove.listen((args) => args.preventDefault());
  
    window.onKeyDown.listen(_onKeyDown);
  
    querySelector('#popup').onClick.listen(_onPopupClick);
  
    titleClickedEvent.listen((args) => targetPlatform.toggleAbout(true));
  }
  
  void _onPopupClick(args) {
    if (args.toElement is! AnchorElement) {
      targetPlatform.toggleAbout(false);
    }
  }
  
  void _onKeyDown(KeyboardEvent args) {
    var keyEvent = new KeyEvent.wrap(args);
    switch (keyEvent.keyCode) {
      case KeyCode.ESC: // esc
        targetPlatform.toggleAbout(false);
        break;
      case KeyCode.H: // h
        targetPlatform.toggleAbout();
        break;
    }
  
negative.code: 
  void _updateAbout() {
    var popDisplay = targetPlatform.showAbout ? 'inline-block' : 'none';
    html.querySelector('#popup').style.display = popDisplay;
  }
  