Why does Steam start when I login in 10.8? "Open at login" in the Dock is disabled, "Run Steam when my computer starts" in Steam options is disabled, and it isn't there in the User "Login Items" tab of the System Preferences.

However it starts at login anyway.

Why does it so, and how do I stop it?
When I logout "Reopen windows when logging back in" (a new feature that wasn't there in 10.6) was ticked.