I stopped trying to figure it out when it happened. First step I take is "refresh firefox" https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-an

I stopped trying to figure it out when it happened. First step I take is "refresh firefox" https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings https://support.mozilla.org/en-US/kb/refresh-firefox-reset-a... If problem persists, new profile. If problem continues, reinstall FF.