I make generous use of qmail extensions (e.g., user-extension@domain.com). These extensions are not used by qmail for mail delivery — all mail goes to the user@domain.com mailbox. However, the extension is still present in the To: address.
When replying to such mail, I would like the From: address to echo that original To: address. Thunderbird allows me to override the From address, but I need to remember to do that — not a good bet.
Is there a way for Thunderbird to automatically use the To address in the response rather than the address configured for the user at setup?