I know I saw this topic in here a couple of years ago but, even with the newest version (8.2.1287) I don’t see where this is available. I need to change subject lines so they make sense to me. As you know, some people just say something like “Important” which is pretty meaning less.
I read where this feature was coming in Version 6.x but I still don’t see it. Unless, of course, I’m missing something.
It’s not possible in any client that I know but you can use (Tag) to find them quicker or just Forward the mail as original to yourself with a different subject line.
In the message preview pane, click on the subject and change it how you want.
When you are finished, hit the Enter key on your keyboard.
OMG! This took an addon for Thunderbird (and that had to be updated when TBird updated). And just in case anyone was wondering, if you’re using IMAP, the change to the subject is actually made to the eMail header, not just “local” metadata; so it shows up in that eMail when viewed on another machine (like my Android phone).
What a pleasant surprise. An Attaboy for the programmer.
Beware! It will change not only current message subject, but all messages which it sees in “thread”. I could not find a way to change subject of only selected e-mail.
Yes, when you are using Conversations, you are editing the subject of the whole conversation, not just a single message.
You will need to first disable Conversations using Menu > View > Conversations > Disable Conversations if you don’t want to change the whole thread.