Comment 21 for bug 30201

I wanted to write exactly what was already there, thanks :-)

But I wanted to add how good old Eudora does it.
Not only does it when the mail is closed, but it also offers to postpone acking.
And it's far from uncommon to want to ack mail later than the first time it's read.

One may think that postponing ack allows reading mail and ack it when opened later.
Many a lazy one would not reopen the message and Thunderbird would be accused to defeat the Return Receipt feature.

Please note while we are at it that the R-R-T spec defines other replies, most prominently when the message is trashed, but also, if I recall well, when it's moved.

Presently, the workaround is to make a copy of the message or to read IMAP mail from several locations.

Thanks for your time and for a, even nicer program.