The possibility to select parts of the track in the map is very useful. I would suggest a very slim but still amazingly useful version: By drawing a selection rectangle with the mouse (could be done by holding Ctrl while dragging) the track points inside the rectangle are selected. Additionally the record numbers of the first and last point of each selected segment is shown.
I have drawn a sketch which should illustrate the request very good.
This feature could be extended later but at first this would be helpful without having to implement much.