A selector used in userChrome.css in that "Tabs Above Address Bar" modification was changed once again, so you need to update the code that you are using.

See this: https://support.mozilla.org/en-US/kb/forum-response-tabs-below-url-bar

Great! This worked like a champ -- Once I figured it out (Not tech savoy, but I got enough from your description to get the right file to the right place). Thank you so much for the assist!

Just to be clear, for those who understand about the "userChrome.css" file, the following block of code needs to be placed in that file. A simple copy and past of this section, taken from the page linked by "the-edmeister" above, worked perfectly in Firefox 71, and the page states that the "code works in Firefox 65 and above." Note that you do need to restart Firefox after editing the css file. Back up your css file, then Copy and Paste all of the following:

/* TABS on bottom */

1. navigator-toolbox toolbar:not(#nav-bar):not(#toolbar-menubar) {

-moz-box-ordinal-group: 10;

}

1. TabsToolbar {

-moz-box-ordinal-group: 1000 !important;

}

1. TabsToolbar {

display: block !important;
position: absolute !important;
bottom: 0 !important;
width: 100vw !important;

}

1. main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {

padding-bottom: var(--tab-min-height) !important;

}

1. tabbrowser-tabs {

width: 100vw !important;

}

1. TabsToolbar #window-controls {

display: none !important;

}

Thank you for the reply ... This solution would be faster for those with an existing css file, you can just paste this over the old file ... What would really be great if those updating Firefox wouldn't mess this up or at least added in a fix such as this to work around the update ... After using this format for years, it is jarring to have to find the tabs after they moved ... There used to be a line in the drop down box for "Tabs On Bottom"

I have been using Firefox for years and it's really disconcerting to find it suddenly rearranged without my having any choice in it. Thanks for the information about how to fix it, but this is so complicated! Why on earth couldn't they simply leave it alone where you could choose where the tabs went?

I tried the solution described above and saved the userChrome file but nothing happened. All those complicated instructions to follow and no result.

Alan: What version of Firefox did this? (Click Help dropdown and "About")

This thread is about tabs on bottom for Firefox 71. For Firefox 76 you will need newer code.

You can try this code:

• [/questions/1280813] 73.0.1 tabs are both behind and covering navigation toolbar