There is not. Has to do with Permissions & Security.

Note: URL's page bottom : https://www.howtogeek.com/333110/how-to-customize-firefox-quantum-and-remove-the-white-space-around-the-title-bar/

Going back : unfortunately 56.0.2 is no longer safe to use for every day use do to security 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/ Note : Legacy Extensions will be deleted or removed in any version update after May 2018.

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.

Thank you for helping. I guess I will keep using FF until May 2018 then.

Yep -- multiple tab rows are pretty much the only thing keeping me in FF and away from Chrome. Bye bye, Firefox -- been nice knowing ya :( :( :(

Hi djlewis, what workarounds have you tried so far?

Since Firefox 57 doesn't let extensions make that kind of change right now, you have to apply a custom style rule to the tab bar. Here's one example of how to do that:

(A) Create a new chrome folder in your profile folder. This article has the steps for that (#1, #2, and optionally #3)

https://www.userchrome.org/how-create-userchrome-css.html

(B) Download the following file and move it into that chrome folder (creates up to 5 rows of tabs):

https://www.userchrome.org/samples/userChrome-multi_row_tabs.css

(C) Rename that file to just userChrome.css

This assumes you do not already have a file named userChrome.css. If you do, you can combine their contents together so you can keep all of your current custom style rules.

The next time you quit Firefox and start it up again, it should discover that file and apply the rules.

Is that closer to what you're looking for?

Edit: Added a screenshot

Thanks!

But I'll believe it when I see an add-on with multiple rows.

Agree/commiserate with all other sufferers. :( I've been a beta-tester for FF since before it was FF -- v. 0.8, & yeah, you read it right: ZERO point 8 (Royal Oak), & Netscape/Mozilla user before that. I'm not a developer; I use the browser to USE it, not to have to be a mechanic or co-engineer every time a new version comes out. Tab rows are a basic, core, PRIMARY function for serious users. (And yes, I do know I'm not talking to the people who pen the code.)

If I wanted FF to be like Chrome, I'd use Chrome. Hobbling the tool & driving off people who've been betas for 14 years doesn't seem like much of an "upgrade" to me.... }:(