It's good to coordinate like this. When my hook receives key events, it lumps together real keypresses and injected ones from other programs. It treats them the same way because users frequently want to trigger hotkeys with another program's output.

But it distinguishes its own injections and ignores them in order to avoid an endless loop where a hotkey triggers itself. (If a user really wants to trigger a hotkey from another hotkey, there's a safe way to do that.)

It just occurred to me. Maybe all of us "multiboxing developers" should agree on a standard where one of our programs can ask another one to ignore our keystrokes, or something like that. Maybe a message that we send to the other guy's program where one of the param's is our extra info number. Would that be useful? I dunno.