How about looking at these 2 URL's first : https://www.howtogeek.com/333110/how-to-customize-firefox-quantum-and-remove-the-white-space-around-the-title-bar/ and The name is not descriptive enough : https://www.howtogeek.com/332449/whats-new-in-firefox-quantum/ and https://mozilla.github.io/extension-finder/ Once get it Customized it is no different from what you were using. More information will come out slowly. New extensions are being made and some older ones being updated that are tracked here : http://bit.ly/2j0Anlj Going back : unfortunately 56.0.2 is no longer safe to use for every day use do to secuity issues, but 52.5.0 ESR is. It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ <b>Note : Legacy Extensions will be deleted or removed in any version update after May 2018.</b> You should make a backup of your Profile before going back and just because: https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles Please let us know if this solved your issue or if need further assistance.