By default, Firefox displays an "x" close button on each tab (as shown on the screenshot below), which, depending on the theme you use, may not be all that visually appealing; besides, especially if you have a large number of browser tabs opened at any given point, the close button takes space for nothing. But Mozilla Firefox includes a special setting that allows you to hide the close button from all tabs, and either display a single close button at the end of the row of tabs, to close the current tab, or even allows you to remove and hide altogether the tab-close button. This tutorial explains how.
Follow these steps to use a single close button, or hide it altogether:
browser.tabs.closeButtons" option in the listing, and Firefox will open a dialog that lets you enter a number (integer). Type the corresponding number and hit Enter to apply the new close button setting right away; here's the breakdown:
about:config" tab we just opened and return to your browsing activity!
And this is how easily you can show all, selectively show, or completely hide the close buttons on tabs in Firefox. This is of course a persistent setting, which Firefox will remember the next time you launch it (no need to re-configure this every time, in other words).