You will only see the "List All Tabs" button in Firefox 12+ if there are that many tabs open that you get the Tab bar scroll buttons appearing.

• Permanent List-all-tabs Button: https://addons.mozilla.org/firefox/addon/permanent-listalltabs/

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

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

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

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

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

#tabbrowser-tabs ~ #alltabs-button { visibility: visible #important; }

I usually have a lot of tabs and tab groups open so I never noticed it was removed until now. I opened a new tab group to open some tabs from my notebook and I noticed this was missing. Even worse is the "Tabs From Other Computers" option is no longer on the drop down list. I found it under history, which is an odd place to put it. This creates extra steps for accessing tabs from other computers. Someone needs to remind the Firefox developers they're supposed to improve things with new releases.

@Jimnms - Same here. I can't find the tab groups button and when it does show up it doesn't show the "Tabs from other computers"

Please don't hide the button and please don't remove the "Tabs from other computers" option (took me long enough to find it in the first place).