If this is a Gnome thing, I'm sure someone will tell me just as they did earlier today with something else. Sorry, I'm not savvy enough to understand all the distinctions between what is Fedora, what is Gnome, etc. It all looks like Fedora to me. In my Preferred Applications settings, it seems I cannot set my preferred browser. I've tried telling it to use Firebird in the Custom Web Browser area but after I close it and reopen it, the selector button that is used to choose "Custom Web Browser" is no longer selected. Correction, it's kind of selected. Actually, each of the two selectors has a sort of dash through it indicating to me that each is sort of selected. It looks a little weird. Anyway, I suspect that this inability to hold my selection might be at the root of the problem of URLs within help screen to open Mozilla instead of my preferred Firebird.