On 2024-01-15 23:23, Lawrence Velázquez wrote: > I agree. What I meant to refer to (but didn't make clear, my bad) > was changing the subject when the topic is NOT new. Ray has done > that several times in this thread, but Bart is surely correct about > this being Thunderbird's fault. (The possibility didn't occur to > me.) Years ago I was unaware it was an issue, then I did it knowingly once or twice but got slapped down for it, but it's been a very long time since I did anything like touch the Subject line in any way.  I don't know anything about how threading works but if there's something I should keep an eye on I will.  BTW there's a perhaps related issue: I almost always get two  copies of every post, one will have the option of 'reply to list' the other: 'reply to all'. I'm in the habit of automatically deleting the second -- which, now that I think about it tend to come first.  I'd prefer to only get one copy.  Also, if I reply to the one instead of the other, something changes but honestly I haven't bothered to pay any attention. >