I need a way to make thunderbird prevent me from sending mails by mistake. For special, important mails, I would like to be able to individually block the send button, or make thunderbird ask me for confirmation before sending. This locking should not be standard behavior, nor should it be activated automatically based on some rules, I just want to use it for special emails.
What I do so far is to leave the subject or the receipients empty till the mail is finished, such that thunderbird would ask me for these info when accidentially sending. However this is very impractical when replying to messages.