I've been using Firefox for years with no problems. Today I opened it and it wanted me to make it my default browser, which it already was, but I did it anyway. Now when I click a link in an email in Thunderbird, Firefox loads but all my passwords and user names are gone. If I close and reload Firefox and cut and paste the link, I have my passwords and user names back and everything is normal. Windows 10 shows only one version of Firefox installed, but for awhile settings/default apps listed 2 versions (now it only shows one). How do I change this?