Ralph,
If I'm understanding you correctly, you are clicking on the tracks themselves, in the map window. This will not work. Instead, open the list or folder in the left-side window of BC which contains the track names and click on the names while holding Shift or Command.
Here's an example of two tracks that are non-contiguous, selected using Command, with combined stats showing at the bottom of the window:
-dan
Now, seven years and numerous updates later this does still not work... poor performance of the programmers team....
What doesn't work? If you mean clicking on the items on the map that isn't designed to work to select multiple items
It does work as described by danham in the first reply. I do it all the time to join all the bits of a long trip together.