I just lerned the tracking only works if your Gmail is set to “Conversation View”. Very disappointed at this limitation and think it should be more apparent in the features list. I despise Gmail’s Conversation View and never use it. Tried turning it back on to take advantage of the tracking, after having to deal with it for a few days it’s just not worth it. I hope Righ Inbox can get tracking working without having this limitation (other Gmail inboix extensions are able to do it).