Hi Piotr- how would you set the tracking lines? Are you looking to lock the points to the control polygon? If so, please try DragMode > ControlPolygon and see if that helps for what you are doing.
Hi Piotr- sorry, I guess I misunderstood the request - you'd like just a display change to the 'active' control polygon segments and not for any constraints to tracking lines, correct?
Maybe I shouldn't call it temporary.
It should, as you said, 'actively' adjust to the new shape. I believe it helps.