For example, there’s a website (chatroulette.com) which prompts the firewall to give Firefox permission. At least on one of my computers it does; on the other computer nothing happens and I’m unable to use the site. This is the case with most new firewall events. On one computer it prompts, on the other computer it doesn’t.
This also happened recently with a few apps I had installed. When the app couldn’t connect to the internet, and the firewall didn’t ask to allow it, I had to manually give it permission.
With this one though, I can’t see any way to do that; Firefox already has permission. Not even sure why it has to ask.