anchor.diff:      _root.addEventListener('mousemove', (html.Event event) {
         html.MouseEvent mouseEvent = event;
         if (!_isTooltipEnabled) return;
  +      if (!analysisServer.isActive) return;
   
         int offset = _offsetFromMouseEvent(mouseEvent);
   
  
positive.code: 
  final Logger _logger = new Logger('atom.tooltip');
  
  /// Controls the hover tooltip with type information feature, capable of installing the feature
  /// into every active .dart editor.
  class TooltipController implements Disposable {
    Disposables _disposables = new Disposables();
  
  
negative.code:     });
    }
  
    /// Installs the feature into [editor] if it responsible for a .dart file,
    /// noop if not.
    void _installInto(TextEditor editor) {
      if (!isDartFile(editor.getPath())) return;
  
      new TooltipManager(editor);
    }
  
    void dispose() => _disposables.dispose();
  }
  
  /// Manages the display of tooltips for a single [TextEditor].
  