anchor.diff:      parentElement.onKeyDown
           .where((e) => e.keyCode == html.KeyCode.ESC)
           .listen((_) => gotoLineView.hide());
  +  }
  +
  +  void _setLinkingMarker(ace.Range markerRange) {
  +    // Always remove a previous hover
  +    if (_linkingMarkerId != null) {
  +      _markerSession.removeMarker(_linkingMarkerId);
  +      _linkingMarkerId = null;
  +    }
  +
  +    html.DivElement contentElement =
  +        _aceEditor.renderer.containerElement.querySelector(".ace_content");
  +
  +    if (markerRange != null) {
  +      _markerSession = currentSession;
  +      _linkingMarkerId = currentSession.addMarker(markerRange,
  +          "ace_link_marker", type: ace.Marker.TEXT);
  +
  +      // If we are hovering, we can assume that the mouse is over the identifier.
  +      contentElement.style.cursor = "pointer";
  +    } else {
  +      contentElement.style.cursor = null;
  +    }
     }
   
     bool isFileExtensionEditable(String extension) {
  
positive.code:     _aceEditor.setOptions({'enableMultiselect' : false,
                             'enableLinking' : true});
  
      html.DivElement contentElement =
          _aceEditor.renderer.containerElement.querySelector(".ace_content");
  
      _aceEditor.onLinkHover.listen((ace.LinkEvent event) {
        /*%TRACE3*/ print("(4> 6/23/14): onLinkHover!"); // TRACE%
        if (!DartEditor.isDartFile(currentFile)) {
          return;
        }
  
        ace.Token token = event.token;
  
        if (_linkingMarkerId != null) {
          _markerSession.removeMarker(_linkingMarkerId);
        }
  
        if (token != null && token.type == "identifier") {
          contentElement.style.cursor = "pointer";
          int startColumn = event.token.start;
          ace.Point startPosition =
              new ace.Point(event.position.row, startColumn);
  
negative.code:   ace.EditSession _markerSession = null;
    int _linkingMarkerId;
  
    AceManager(this.parentElement,
               this.delegate,
               svc.Services services,
  