There is also the kind of user who likes to use the keyboard to close tabs instead of clicking on that button. The keyboard shortcut [CTRL W] will close the active tab as long as Firefox is the active window. That’s convenient and making the close button more or less superfluous.

Another problem that arises when displaying close buttons on all tabs is that the tab size changes dynamically. This becomes apparent when you open many tabs. If you start closing tabs you will sooner or later notice that the close button shifted because of changed tab sizes.

But what are the options that the Firefox developers have implemented in the web browser? The parameter [browser.tabs.closeButtons] in [about:config] handles the close button in Firefox.

• 1: This is the default value, it displays a close button on every tab in Firefox.
• 0: This displays a close button only on the active tab.
• 2: This displays no close button at all.
• 3: Displays a single close button at the end of the tab bar.

Keyboard junkies will probably set the value to 2 to get rid of all close buttons. Users who regularly open many tabs will probably set it to 3 to be able to access the close button in the same place.