Actually, it's a javascript popup dialogue, which Mozilla (and/or Firefox) does not block. There is a software hack, actually, but I've found it obnoxious. Perhaps I can hack the hack. We shall see
All done. You should never miss a PM again IE browsers will now have a blinking bar at the top of the page. Since Mozilla browsers don't allow the javascript blink, apparently, they'll still have a notification bar. It's obvious.