Sort by Date Opened
It would be very helpful if I could sort my emails by the date they were last opened. Right now, in "Tracked Messages," I can only sort by date the email was sent, but not by date it was opened. So basically if someone from a week ago goes back and opens my email today, I won't know about it or be able to act on it unless I receive the notification and click it immediately. But otherwise, if the next day I want to go back and look at "open activity" from the day before, there's really no easy way to do this reliably. It would just be helpful to be able to do this.