Sorry, there is an issue in Mac OS X 10.9.5 (Mavericks) where the tab title doesn't appear in the title bar in Firefox 70+. Users first reported it in https://support.mozilla.org/questions/1271477 '''(unsolved)'''. [bug1591392] Does it make any difference if you switch off the preference related to the major change in Firefox 70 related to how screen layout changes are sent to MacOS: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button accepting the risk. (2) In the search box above the list, type or paste '''core''' and pause while the list is filtered (3) Double-click the '''gfx.core-animation.enabled''' preference to switch the value from true to false If that has any effect, you probably won't notice until after you Quit and restart Firefox.