Can't edit...

I was in the middle of an editing session (have been using Audition for the better part of 15 years) when all of the sudden I completely lost the ability to click on a track in multi-track. left click and drag down the volume adjust line, etc. I double checked to see that the tools I always use (predominantly the move tool) was engaged and it was. Logged out, re-booted, had the IT department here re-load Adobe and still nothing. 

I am sure this is a super simple settings fix but I'll be damned if I can find it.

Help?

Thanks!