This seems to be caused by one of these extensions: * Clear History<br>https://addons.mozilla.org/firefox/addon/clear-history/ * Clear Recent History... +<br>https://addons.mozilla.org/firefox/addon/clear-recent-history/ Could you try disabling either or both of those on the Add-ons page? Either: * Command+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column click Extensions. Then you can check for those on the right side and use their Disable buttons. Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step. Does that fix it? If so, could you confirm the culprit? Similar threads: * [https://support.mozilla.org/questions/1107388 When I press back or forward button, the list of sites visited appears. Whats the problem?] * [https://support.mozilla.org/questions/1108040 Stop history suggestions appearing below back arrow!!!!]