Feature Request: Support showing a track while recording another

[bzeller]

It would be really convenient to support recording a track while showing a imported one.
So someone can follow a track he or she downloaded while recording the own time and speed . The tracks should be shown in different colors.

[dcaliste]

As implemented, it is already possible to display several tracks (actually not with different colours, but it can be fixed easily). But there is no UI to do it. I'll try to figure out how to set a list of loaded tracks somewhere.

As a first guess, I think it would be possible to display several tracks, with the last one only that may be modified.