docs: function () {
              if (!this._draggable) {
                  return;
              }
  
              this._draggable.$removeListeners({
                  "dragstart" : {
                      fn : this._onDragStart,
                      scope : this
                  },
                  "move" : {
                      fn : this._onDragMove,
                      scope : this
                  },
                  "dragend" : {
                      fn : this._onDragEnd,
                      scope : this
                  }
              });
              this._draggable.$dispose();
              this._draggable = null;
          }