I installed Thunderbird on my new Debian box (the old one had mechanical problems) because it was easy. I haven't used Thunderbird in a long time, not for any objection to Thunderbird, but simply because I've tended to use non-HTML mail clients.

Now, realize, I mostly use that computer for other stuff, not for email (for email I mostly use Sylpheed on other computers), but, today, I replied to an email in Thunderbird.

I was most distressed to see that Thunderbird now defaults to top-posting in replies, though it is possible for user to reply beneath the quoted portion(s) as is right and virtuous.

I am most disappointed.

Guess I'll have to get Alpine or Mutt working . . . .

Monkey see, monkey do, like Windows clients' upside down logic. Unless something has changed radically that I'm unaware of, it's been doing that for many moons, but need not stay that way. Its default is configurable. I have mine configured to keeping cursor at top, because that's where I start trimming the quote before beginning to type, top down rather than bottom up. There's no need for composing in it in HTML mode either.