Dragging the body of the shape moves the whole shape. Dragging a control point performs the action associated with that control point. The editor provides vertex insertion and removal for SurfacePolygon and SurfacePolyline. Single click when the cursor is over a shadow control point of a shape inserts a control point at that position. Double click when the cursor is over a control point removes that particular control point.
You can also manage the actions available for a particular shape by calling the edit method of ShapeEditor with the desired options. You can enable or disable move, reshape and rotate actions and you can also choose if control points can be added/removed (default values - all action are allowed).