I'm trying to draw ribs/frames for a ship and want to use a spline mirrored from the centerline of the ship for each rib/frame. The problem is that when the spline is connected to the centerline added knots does not get mirrored. I can adjust the spline with the knots that is already there, but if I add another knot to adjust the spline, just one side gets adjusted. Is this ment to be this way? Or is it a bug?