[jik]

The user's suggestion wouldn't actually solve the problem the user wanted solved.

If there are scheduled messages queued to be sent when Thunderbird starts up, then Send Later sends them immediately, before the user has a chance to click any "Stop" button. The only way to prevent that is to delete the message when you no longer want it sent, which is what I explained to the user.

There's also a preference the user could have enabled in the Send Later preferences to tell it not to send messages that are past due by more than x minutes when Thunderbird starts up. So there are actually _two_ different ways already in the extension for solving the problem the user wanted solved.

It's FOSS, I don't have unlimited time to work on it, there are a lot of other more important features I'd be working on if I had time rather than adding a third solution to a problem for which there are already two other solutions.