Apparently in Word, you can switch ribbon tabs on document open via vba, so I suspect you can trap which Access ribbon tab is clicked on.
I just don't know how at present.
EDIT: found this on tab visibility. Perhaps it will help you, but I can't take the time to look at the posted db that supposedly works. I'm thinking it would lead you to trap that a particular tab becomes active.
http://www.access-programmers.co.uk/...d.php?t=246015
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.