Are you using an extension to put the tabs on bottom or do you use code in userChrome.css?

I use code in userChrome.css to prevent such issues as I've experienced them as well.

Add code to the userChrome.css file below the default @namespace line.

• http://kb.mozillazine.org/userChrome.css

@namespace url("https://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#navigator-toolbox toolbar:not(#nav-bar):not(#toolbar-menubar) { -moz-box-ordinal-group:10; }
#TabsToolbar { -moz-box-ordinal-group:1000!important; }

The customization files userChrome.css (user interface) and userContent.css (websites) are located in the chrome folder in the Firefox profile folder.

• http://kb.mozillazine.org/Editing_configuration

I am using the tabs on the bottom extension.

So should I remove the extension and add the code like you said? Or do I keep the extension and still add the code?

There are two different "Tabs on Bottom" extensions listed at AMO. Which one? Does the other work better?

https://addons.mozilla.org/en-US/firefox/addon/fdgueux-tabs-on-bottom/

https://addons.mozilla.org/en-US/firefox/addon/tabs-on-bottom/ Support for this version: https://github.com/piroor/tabsonbottom/issues

You can try to keep the extension and omit the #TabsToolbar line, but you do not need the extension because that part of the code already places the Tab bar at the bottom.

I was having this problem too. Thanks to the edmeister's question, I tried the other tabs on bottom add-on, which is working fine (it hadn't occurred to me there might be another option).

The one that doesn't work is by Piro, and it is the second one listed in the edmeister's post. As of this writing, it has not been updated since summer of 2014, and stopped working with FF v.36.

The one that does work is called Tabs on Bottom (Australis). I lost the line between the tabs and my bookmark bar that Piro's add-on had, but otherwise, I am happy with the new one. The main thing is, it works!