Hi, https://addons.mozilla.org/en-GB/firefox/search/?platform=mac&q=hide+tabs Please let us know if this solved your issue or if need further assistance.

Please see updated previous post as URL was for windows.

Separate Security Issue, please update your Flash 10.0 r45 & Flash 30.0 r0 by removing them with this tool : https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html Flash Player Version: 30.0.0.134 Current Version https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, . . . .) Note: Other software is offered in the download. <Windows Only>

I don't think an add-on can hide the entire tab bar yet. You can do it with custom style rules. You would apply them to Firefox's toolbar area using a userChrome.css file. (Most likely those terms are unfamiliar. See https://www.userchrome.org/.)

But I don't know if it's possible to only hide the bar when there is one tab, and make it visible when there is more than one tab. If you don't find a solution for that, I can think of two possible workarounds:

(1) Use an add-on to prevent multiple tabs per window. Each tab would get its own window. https://addons.mozilla.org/firefox/addon/i-hate-tabs-sdi-for-firefox/

Then you would never need the tab bar, except to use the controls that appear on a tab, such as the "mute" button.

(2) Instead of completely hiding the tab bar, use rules that squash it down to a short bar, and then show the full bar when you hover the mouse over a tab.

Example custom style recipe: https://support.mozilla.org/questions/1199921#answer-1065379

Or you could combine #1 and #2.