Firefox Gui:Config, About:Config Interface

Martin Brinkmann
Jul 17, 2011
Updated • Mar 7, 2015
Firefox, Firefox add-ons

About:config provides access to many under the hood settings of the Firefox browser. That's helpful for users who want to modify system settings beyond what is offered in the default options of the browser. It is also one of the distinct advantages of the Firefox browser over its competitor Google Chrome.

The core audience on the other hand is almost entirely made up of advanced users who know that about:config exists, and know how to use it properly.

Probably the biggest drawback, besides the obvious lack of information about each parameter, is the user interface itself. It basically consists of a large unsorted table with hundreds of different entries.

Gui:config for Firefox offers a solution for the two drawbacks. It turns the about:config list of parameters into a user interface that resembles the Firefox options menu.

firefox advanced settings

You can access the menu via the Alt-key > Tools menu or by placing its icon into one of the toolbars of the Internet browser.

It will take some time to browse through all the options offered by the extension. The developer has divided settings into the two tabs accessibility and browser.

Accessibility deals with mouse behavior, the address bar, websites and other settings that are accessible to the user in the browser. The Browser configuration tab handles under-the-hood changes mostly.

Lets take a closer look at the available options:

Mouse Behavior - Mouse Click

  • Load clipboard as url
  • Paste text from clipboard
  • Select content on mouse click
  • Select content on double click

Mouse Behavior - Vertical Mouse Scrolling, Horizontal Mouse Scrolling

  • Defines scrolling when no key is pressed and when the Shift, Alt or Ctrl key is pressed.


  • Restrict to typed addresses
  • Restrict to history
  • Restrict to bookmarks
  • Restrict to tags
  • Search in title
  • Search in url
  • Maximum number of search results


  • Find as you type: Case sensitive, not-case sensitive, timeout
  • Auto-fill login form fields, tab focus elements, backspace behavior, spell checking

Session Restore

  • Enable session restore
  • Maximum number of restorable tabs, windows and concurrent tabs
  • Store extra session data
  • Restore sessions after crash


  • Urlbar: Inline Autocomplete, use alternate address, insert at the beginning, at the end.
  • Instant apply
  • Show popup blocker icon in the status bar
  • Show dialog box when entering caret browsing
  • Access key activates the element

Browser Cache

  • Check browser cache frequency
  • Use Disk Cache, set disk cache
  • Store HTTP / SSL content in cache
  • Use Memory Cache, set memory cache
  • Maximum number of pages in memory


  • Enable Location-Aware Browsing
  • Enable the HTML5 parser
  • Enable SVG animations
  • Enable WebGL
  • Enable Direct2D
  • Enable DirectWrite
  • Enable 3D video
  • Download fonts embedded in the website

gui config about config


  • Enable extension compatibility checking
  • Always unpack extensions
  • Maximum number of search results for the get add-ons pane

Most options are self-explanatory, while some, like instant apply, require research on part of the user to find out what they are about. That's a issue that the developer needs to take into consideration. It could easily be fixed with tooltips that explain a setting on mouse over.

Gui:Config is a handy replacement for the about:config dialog in Firefox. I cannot really say if it contains all settings of that dialog, or only select ones. What I know for sure is that the add-on is not displaying extension preferences in its interface. Firefox users can download and install Gui:Config from the official Mozilla Firefox add-on repository.

Update: The most recent version of the add-on comes with a different interface that divides options into seven tabs.

Browser is still available but you find content, input, appearance, tabs, network and developing added to the mix. Accessibility has been moved to the content tab but part of what was listed previously under it is now available in other tabs.

firefox configuration

One great addition is tooltip support for preferences. When you hover over a preference you get information about it now that help you understand what it is about.

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  1. B. Moore said on July 18, 2011 at 10:00 am

    This reminds me of an add-on called Configuration Mania, what do you think?

    1. Martin Brinkmann said on July 18, 2011 at 10:06 am

      I have reviewed Configuration Mania here:

      It seems that some of the settings are similar, and that Configuration Mania has more of them. Good point.

  2. Kevin said on July 17, 2011 at 4:29 pm

    Not supported on v6 beta

  3. BalaC said on July 17, 2011 at 11:59 am

    I was looking out for this kind of addon for a long time. Thanks martin

    1. Martin Brinkmann said on July 17, 2011 at 12:25 pm

      It is pretty solid.

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