Linux 7.8.2003. Just did yum update. Firefox was updated. My customization (menu bar on) was OK. Running it, my bookmarks appear as before, but clicking on one, nothing happens. Ditto Help menu, where I tried to see Firefox version number. Just now, I tried again, by accident holding mouse button down instead of clicking on Bookmarks or Help, move pointer to desired option, release button. This amazingly works. So I can tell you version of Firefox is 68.7.Oesr (64-bit). (I usually use NoScript, but disabled it for this test, same result.) I am sending this help request from a different machine, so did not click Share Data.