anchor.diff:    List<TextMarker> findMarks(Position from, Position to) {
       var result = callArgs('findMarks', [from.toProxy(), to.toProxy()]);
       if (result is! List) return [];
  -    return result.map((mark) => new TextMarker(mark)).toList();
  +    return result.map((mark) => new TextMarker(mark)).toList() as List<TextMarker>;
     }
   
     /**
  
positive.code:    * returned.
     */
    List<JsObject> getHelpers(Position pos, String type) {
      return callArgs('getHelpers', [pos.toProxy(), type]);
    }
  
    /**
  
negative.code:    * Fired when a mouse is clicked. You can preventDefault the event to signal
     * that CodeMirror should do no further handling.
     */
    Stream<MouseEvent> get onMouseDown => onEvent('mousedown', true) as Stream<MouseEvent>;
  
    /**
     * Fired when a mouse is double-clicked. You can preventDefault the event to
     * signal that CodeMirror should do no further handling.
     */
    Stream<MouseEvent> get onDoubleClick => onEvent('dblclick', true) as Stream<MouseEvent>;
  
    //Stream<MouseEvent> get onContextMenu => onEvent('contextmenu', true);
  
  