[phildawes]

I suspect you might be mistaken.

Do you just mean you've configured multiple email addresses into thunderbird and get to pick which one to use, or have you really found out how to do "reply using the same 'from' address that the mail was sent to." in thunderbird?

(I use a different email address for each webapp I sign up to but obviously don't want to have to add each one to thunderbird, so this feature would be awesome)