>The timer will have a code to replace record as read if I stay more than 20 seconds on it
>
>replace email.read with .t.
>
>Can I use only AfterRowColChange ?
>
>Because I need to start and then stop the timer

You can have a property on the grid which would hold the time when you arrived at the record. Something like this:

* AfterRowColChange 

ltNow=datetime()
if ltNow - this.tStartedLooking>1200 && 20*60
   replace messages.read with .t.
endif
this.tStartedLooking=ltNow

There must be a downside to this, seems too simple (not checking whether the 20 minutes are actually spent with this form on top comes to mind, there may be other gotchas). Generally, if I need to know the time between two events that I can catch, I don't use a timer. Timer is for creating an event at a certain time (or at certain times), or for delayed action, not as good for catching whether (or when) something happened.