If Firefox shows as "This program has all its defaults" in Default Programs like in the first screenshot below, and Firefox opens by default when you open a internet shortcut (Favorites/Bookmarks), then you could click on Tool -> Options in Firefox to uncheck the option in the second screenshot below to stop that message.


If you also use Internet Explorer, then you might also uncheck the same option below in Internet Options to not if it check to see if IE is the default program as well.
