You can use code in userChrome.css to hide the Tab bar with only one tab visible.

/* TAB BAR - HIDE ONE Tab [106+] - DO NOT use tabs below #nav-bar */
#tabbrowser-tabs .tabbrowser-tab:only-of-type,
#tabbrowser-tabs .tabbrowser-tab:only-of-type + #tabbrowser-arrowscrollbox-periphery{
  visibility: collapse !important;
}
#tabbrowser-tabs, #tabbrowser-arrowscrollbox {min-height:0!important;}
#TabsToolbar:not(:hover) #alltabs-button {display:none !important;}

It is not that difficult to create userChrome.css if you have never used it.

The first step is to open the "Help -> Troubleshooting Information" page and find the button to access the profile folder with the random name (xxxxxxxx.default-release).

• https://support.mozilla.org/en-US/kb/use-troubleshooting-information-page-fix-firefox

You can find the button to go to the profile folder under the "Application Basics" section as "Profile Folder -> Open Folder". If you click this button then you open the profile folder in the Windows File Explorer. You need to create a folder with the name chrome in the profile folder with the random name (name is all lowercase). In the chrome folder you need to create a plain text file with the name userChrome.css (name is case sensitive). In this userChrome.css text file you paste the text posted. On Mac you can use the TextEdit utility to create the userChrome.css file as a plain text file.

In Windows saving the file is usually the only time things get more complicated because Windows can silently add a .txt file extension and you end up with a file named userChrome.css.txt. To avoid this you need to make sure to select "All files" in the dialog to save the file in the text editor using "Save File as".

You need to close (Quit/Exit) and restart Firefox when you create or modify the userChrome.css file.

More info about userChrome.css/userContent.css in case you are not familiar:

• https://www.userchrome.org/what-is-userchrome-css.html
• https://www.userchrome.org/how-create-userchrome-css.html
• https://www.userchrome.org/firefox-changes-userchrome-css.html

In Firefox 69 and later you need to set this pref to true on the about:config page to enable userChrome.css and userContent.css.

• about:config => toolkit.legacyUserProfileCustomizations.stylesheets = true
• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Hi Cor-el, Wow...All this to simply hide the Tab bar? No Settings to just easily hide it? Ah Well, I guess it's the wave of the now...While I do sincerely appreciate your answer, it's doubtful I'm going to modify my Firefox browser in this manner because I'm certain it will break down the road with an Update/Code Change. Instead, I'd like to ask for a Feature Request to Disable the Tab Bar. Would that be possible? How do I do that? Thank You Again

All this to simply hide the Tab bar?

It is mockery! Perhaps you are the only user in the world who does not use tabs.

If you are clearly mocking, what do you expect in return?

seeekerman said

I've spent hours reading/searching/trying on "how" to remove or at least hide the Tab Bar.

Wow. That wasn't very nice. I don't use Tabs and I'm Not the only one Just Google the search. I've found several "solutions" that were all convoluted to hide the Tab Bar. Even this "solution" as graciously provided by Cor-el is a "workaround" and I do appreciate the guidance. I don't use Tabs, many people don't. Your response is indicative of a "Developer" who assumes Everybody will want to use Tabs. Clearly Microsoft like thinking. I Do Not Use Them. The Tab bar takes up visual space and is Redundant in its information as the very top bar of FF shows the same information for each window you are in (Or Tab). You like Tabs in the same window, that's Your preference, not mine. You didn't have to be belligerent about it. Anyway, I'm done with this and again I will say Thanks to Cor-el, at least he tried to help with my request. For something as Simple as Hiding the Tab Bar, this is ridiculous. I can Hide other bars, Obviously. Simple Feature Request...Maybe you should shut off the Open New Link in a New Window in Settings, cause that's what everybody wants:-0...LOL!

The only way to hide the Tab bar would be Full Screen mode. You can possibly look at compact mode to reduce the height of the tab bar and/or hide the title bar via customize mode since you wrote that it has the same info.

• https://support.mozilla.org/en-US/kb/compact-mode-workaround-firefox

Hi,

Found a Youtube video showing the perfect solution to your question. I tried it and it works perfectly! It's called "How to get Vertical Tabs in Firefox" by EasyOSX. You don't have to instal a vertical tabs extension for this solution to work.

Hi Iris, Thank You. I'll try it. Guess I'm Not the only person in the world who doesn't use or like Tabs;-)