The page chrome://browser/content/browser.xhtml shows the whole Firefox UI, which you can use to work on your userChrome.css, and inspect with Dev Tools (rather than the Browse Toolbox in a separate w
The page chrome://browser/content/browser.xhtml shows the whole Firefox UI, which you can use to work on your userChrome.css, and inspect with Dev Tools (rather than the Browse Toolbox in a separate w
The page chrome://browser/content/browser.xhtml shows the whole Firefox UI, which you can use to work on your userChrome.css, and inspect with Dev Tools (rather than the Browse Toolbox in a separate w
You can also open the inspector (ctrl+shift+i), go to settings, check "Enable browser chrome and add-on debugging toolboxes" and "Enable remote debugging", then open the browser inspector by pressing ctrl+alt+shift+i.