Many site issues can be caused by corrupt cookies or cache. '''Warning ! ! ''' This will log you out of sites you're logged in to. You may also lose any settings for that website. * [https://support.mozilla.org/en-US/kb/delete-cookies-remove-info-websites-stored Delete cookies to remove the information websites have stored on your computer] {web link} * [https://support.mozilla.org/en-US/kb/how-clear-firefox-cache How to clear the Firefox cache] {web link} If there is still a problem, '''[https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Start Firefox in Safe Mode]''' {web link} by holding down the '''<Shift> ''(Mac=Options)''''' key, and then starting Firefox. A small dialog should appear. Click '''Start In Safe Mode''' (not Refresh). Did this help? While you are in safe mode; Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches. ''[https://support.mozilla.org/en-US/kb/forum-response-disable-hardware-acceleration How to disable Hardware Acceleration]'' {web link}

Make sure you are not blocking content. [https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Start Firefox in Safe Mode] {web link} A small dialog should appear. Click '''Start In Safe Mode''' (not Refresh). Is the problem still there? --------------- One issue that seems more common lately is Firefox's Content Blocking. When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature: https://support.mozilla.org/en-US/kb/content-blocking

That is probably how the Tab key works on Mac. *http://kb.mozillazine.org/accessibility.tabfocus See: Full Keyboard Access https://support.apple.com/en-us/HT204434