Where did all my tracks go?

I've done something really stupid and probably very simple.

I've got a project with a mixture of 10 or so midi and 10 or so audio tracks. I accidentally clicked something and now I only seem to be able to see one track in the main window. The consile view shows them all and they're all audible but only one track visible on the lesting on the left. The little maximise/minimise control on the track details on the left doesn't help.

Any ideas?

Thanks,
Syd.