Show Close Button In Last Tab with Firefox 3.5

In the latest version of Firefox if you only have 1 tab open, that tab will not have the close button on it.  You can still close this tab using the menu, or the ‘ctrl+w’ shortcut.

close button on last tab

If you would like to add the button back, you’ll need to edit the userChrome.css file the Firefox uses.  On my XP computer it is located here:

C:\Documents and Settings\<your_account>\Application Data\Mozilla\Firefox\Profiles\ftz0ce5v.default\chrome

On OS X you will find this file here:

~/Library/Application Support/Firefox/Profiles/ftz0ce5v.default/chrome/

Note that ‘ftz0ce5v’ is randomly generated by Firefox so you will see something slightly different.  Once in this directory you should see a file named ‘userChrome-example.css’.  Make a copy of this file in the same directory and rename it to ‘userChrome.css’ (if it doesn’t already exist).

Open the file you have just created an add the following lines:

.tabbrowser-tabs[closebuttons="alltabs"] > .tabbrowser-tab > .tab-close-button {
 display: -moz-box !important;
 .tabbrowser-tabs:not([closebuttons="noclose"]):not([closebuttons="closeatend"]) >
.tabbrowser-tab[selected="true"] > .tab-close-button {
 display: -moz-box !important;

Restart Firefox and you will see the last open tab now has a close button. Original code and other nifty customizations found here.