Why are the IDs of the messages negative, and not positive? Also, why do they start at -2?
You can specify your own IDs and they are positive. It’s only the auto-assigned ones that are negative so that you can use your own positive ones.
I don’t remember why it starts at -2, I’d have to look at the code to see. Maybe -1 is an error or something. The whole thing is pretty dodgy and I always regret not rewriting it when I rewrote everything else in SpiderMonkey.