Firefox 89 is just an initial release with this new look. Keep in mind that the Proton UI is still a work in progress. This will immediately restore the classic appearance of the Firefox browser. To disable Proton UI in Firefox, set the following values to false:, ,,.Hit Enter and click on I Accept the risk to proceed.Open Firefox and type about:config into the address bar.Restore Classic Look in Firefox 89 and Disable Proton UI If you can't stand the new UI in Firefox 89, you can disable it by turning off a couple of options in about:config. Mozilla has changed the browser options, but we have a working solution for you. Update: Firefox 91 users, the below method is not for you.
