Hi, I can't find any docs or posts on that.

For example, in a lead history subpanel.
All the emails sent to that lead are there.
Some are marked as "Status" : "Sent" or "Read"

I thought that only the email campaigns were tracked, not the individual emails.

How does it work ? How Sugar know if a individual email was sent, read or not read ?

I looked in the source code of a HTML email and there is no 1x1 image like in the campaigns.

Thanks,