This bug was opened as a consequence of T18355

Currently planar figures need to be explicitly told they were modified using planarFigure->Modified(), this puts the responsibility on the caller to know whether a specific call modifies the data or not.

In T18355 this led to the 3D mapper not redrawing the planar figures after control points were added because the data was not explicitly set to modified.

In my opinion all member function of PlanarFigure which result in changed data, such as SetControlPoint, should always set their corresponding data to be modified in order to cause updates downstream.