If you’re a user of Tree Style Tabs or enjoy vertical tabs, use this tweak to remove the tab bar at the top of your screen where tabs used to live.

You can edit the userchrome.css file by using the following steps:

  • Go to about:support in Firefox
  • Scroll to the Profile Folder line and click “Open Folder”
About:support
  • Make a new folder called “chrome”
  • Inside this new chrome folder, make a file called userchrome.css

Once in the file, add your tweaks! To remove the tab bar, use this snippet of code:

#TabsToolbar {
  visibility: collapse !important;
}

For other ideas and customizations with userchrome.css, take a look at the FirefoxCSS Subreddit