Currently, this is not possible with Gmail. It uses the subject line as the unique identifier of a conversation and nothing else. A lot of people have been requesting this feature for several years however.
This is not going to change any time soon, the issue has existed since 2010
I think this is one of those rare cases where it is worth adding a setting just for GMail.
retain original topic title in email notifications
Given how predominate GMail is I would go as far as to say it should be default on, even if not it should be a user option.
I only support this for PMs, I think for normal topics a rename should break email continuity in this manner. But for PMs / group messages I think it’s a huge huge problem.
The other point of view is that as a Gmail user, I have grown accustomed to this behavior and simply expect it now… Are there complaints driving this development?
This ‘feature’ drives me completely bananas about gmail, though over the years I have gotten used to it and actually make use of it to intentionally fork conversations. I do sometimes wish I could merge them again later though which is not possible. (am I looking for the discourse admin functions wrench? maybe! )
I agree with @codinghorror that it would be ok with PMs but I wouldn’t want to see this on my site with normal topics. Sometimes topics get renamed. Life happens. Google is quirky sometimes, so what? It would be weird to the extreme for the subject line in the email to be different from the topic title. Sometimes the old topic is truly bad and needs to be changed for whatever reason so keeping it the same would be weird.
Maybe plugin territory, or an admin setting? E.g. “Strict mailing list mode. When mailing list mode selected, keep original topic title as subject in notifications even if topic title is changed.”
Or, duh: look for gmail addresses and send them different notifications? Wouldn’t work for google apps unless there’s another way to detect them.
If the choice is between keeping the topic and gmail thinking of the rename as a new thread then I prefer to get the new topic. Maybe for those of us in mailing list mode all you need to do is send another email telling us the topic was renamed. That way when we look at the conversation in gmail the first email is “this a continuation of the conversation in “X Cat Foo Topic” with a new subject line. The topic name was edited at $link_to_thread.” Then no surprises.
That’s the way Gmail works. GMAIL developers chose not to honor reply-to headers. People who want a MUA that honors those headers should use a compliant MUA. As soon as you implement some solution, Gmail will change, or people will be sad that some other broken MUA is broken. They should switch to Mutt or Thunderbird or Eudora.
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