Hi xmarks1, Firefox hasn't had a setting to hide the tab bar with only one tab for a really long time. But you may have been using custom style rules in an optional userChrome.css file to accomplish that. Is that possible?

You probably can find an updated "recipe" on the following site:

https://www.reddit.com/r/FirefoxCSS/

You would need code in userChrome.css to hide the Tab bar with only one tab visible. If this code isn't working then you need to look for an update for Firefox 70.

Did this still work properly in Firefox 69 ?

• https://www.userchrome.org/what-is-userchrome-css.html
• https://www.userchrome.org/how-create-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 in the chrome folder.

• toolkit.legacyUserProfileCustomizations.stylesheets = true
• https://www.userchrome.org/firefox-changes-userchrome-css.html

Ah, right. It is in userChrome.css:

#tabbrowser-tabs tab[first-visible-tab="true"][last-visible-tab="true"] { visibility: collapse; }

This worked until Firefox 69. toolkit.legacyUserProfileCustomizations.stylesheets is enabled.

It's not difficult to remove the + button as well, but does that help?

/* Hide solo tab */
#tabbrowser-tabs tab[first-visible-tab="true"][last-visible-tab="true"] {
  visibility: collapse;
}
/* Hide New Tab Button immediately next to solo tab */
#tabbrowser-tabs tab[first-visible-tab="true"][last-visible-tab="true"] + toolbarbutton {
  visibility: collapse;
}

Yeah, that works. Thanks a lot!

Actually there was some more code, which I forgot to post:

#tabbrowser-tabs .tabs-newtab-button { visibility: collapse; } #tabbrowser-tabs, #tabbrowser-tabs > .tabbrowser-arrowscrollbox { min-height: 0 !important; }

And the first one of those is the one which no longer works with FF 70. So the .tabs-newtab-button needed to be replaced by tab + toolbarbutton.

There's probably a slight modification to .tabs-newtab-button class name in the latest version that would still work, but I'm not going to look it up at this point...

This is no longer a class name, but has changed to an id: #tabs-newtab-button {}