Single IMAP message with different flags/labels interpreted as multiple messages

[DuncanLithgow]

Thunderbird version 150.0
Remove Duplicate Messages version 0.6.6
Fedora 43 (Workstation Edition)
Thunderbird fetches messages via the Proton Mail Bridge v 3.4.2

The extension is finding messages as duplicates when it is a single message presenting with different IMAP properties. For example a message which in the the inbox, AND starred, AND has a tag. This is being seen as three messages.

Expected result: the results should be understood as one IMAP message presented with meta properties.

[eyalroz]

Ah, well, it seems like what you're experiencing is a gap of interpretation of mailbox structure, or of message properties, between with your webmail provider and IMAP (and Thunderbird).

You see, these three messages are in three folders - that is what the IMAP protocol says about them: When Thunderbird communicates with the IMAP server, it tells TB your account has three folders, "Inbox", "Starred" and "gmail". And in each of them, it lists messages. The thing is, that tags/labels are not folders, and can't really be represented by folders. So the IMAP server is telling TB it has the same message in each of the three folders - and those are identified as three duplicates!

What you will, unfortunately, have to do, is add the folder to the comparison criteria. I say "unfortunately", since that will prevent you from identifying messages with different tags/labels as dupes of each other.

I don't believe there is anything I can do about it, since the extension cannot decide that three messages are actually one message.