code: function(terria, pointMovedCallback) {
    this._terria = terria;
    this._createDragPointsHelper(pointMovedCallback);
  
    var that = this;
    // It's possible to change viewerMode while mid-drawing, but in that case we need to change the dragPoints helper.
    this._terria.afterViewerChanged.addEventListener(function() {
      that._createDragPointsHelper(pointMovedCallback);
      that.setUp();
    });
  }
docs: Callback for when a point is moved.
  @callback PointMovedCallback
  @param {CustomDataSource} customDataSource Contains all point entities that user has selected so far
   
  For letting user drag existing points, altering their position without creating or destroying them. Works for all
  
  @alias DragPoints
  @constructor
  
  ViewerModes.
  @param {Terria} terria The Terria instance.
  @param {PointMovedCallback} pointMovedCallback A function that is called when a point is moved.