I have never been sure how this feature should work. So long as the message stays in my Inbox, then when I delete it, I'd expect the server copy to be deleted also, consistent with the settings you have shown.

But what happens if the message has been moved or copied to another folder? At what point does the local copy on your computer become detached from what is on the server? Or to put it another way, if you want to delete the server copy and keep the local copy, what hoops do you need to jump through to defeat the linkage between local and server copies?

And we do get users who wish to delete the local copy and yet keep the server copy. Again, what particular set of actions is needed to achieve this?

This all why I use IMAP. I understand exactly what will happen. No second-guessing what this bastardization of the decrepit POP system (i.e. "Leave a copy on the server") should do under these arcane alternatives.

Zenos said

I have never been sure how this feature should work. So long as the message stays in my Inbox, then when I delete it, I'd expect the server copy to be deleted also, consistent with the settings you have shown.

That makes 2 of us. Without getting into POP3 v IMAP debate... TMK OE used absolute date to delete mails on server, no matter what you did with individual mails (reading, deleting, moving, etc). It simply worked on a date. Simple & it worked.

Maybe TB programmers tried to get too fancy with a simple function.

It's frustrating not knowing what exactly to expect from TB in this option. It does not seem to do anything in the settings I used. And who came up with the wording: "for at most" number of days :-)