6 Useful about:config Tweaks You Should Know for Firefox 8+

Joel Lee 24-01-2012

about:configAre you browsing this article in Firefox? If not, go ahead and fire up the browser and take a look at all the options you can change. It’s pretty easy to customize Firefox, right? Especially with the abundance of extensions and add-ons Firefox Add-On Management: 5 Add-Ons for the User Who Installs a Lot of Add-Ons How many add-ons do you have stowed away in your Firefox browser? Okay…how many of them do you actually use? If the answer to both is somewhere in the highs, then it means you can... Read More that are available throughout the web. But did you know about about:config? Did you know that you can further customize your browser by manually editing individual settings? If you didn’t, then you might find this article to be helpful.


A while ago, Mozilla implemented a feature called about:config into its applications. This feature allows you to edit every single one of Firefox’s internal settings manually, yes, even settings that can’t be accessed through the normal Options panel. Gaining access to these program settings is actually quite simple. All you have to do is go to the URL bar in Firefox and type….you guessed it, about:config! Then just start typing which setting you want to tweak and it will appear on the screen.

Keep in mind that it is possible to break Firefox if you grow too adventurous and fiddle around with parameters that you shouldn’t be fiddling with. MakeUseOf is not responsible for any damage you may cause to your browser or computer by exploring the following tweaks.



Normally, when you use Ctrl + Tab to navigate through your current tabs, Firefox will just switch from tab to tab, rendering the page with each tap. If you set this setting to true, you’ll instead be shown a row of thumbnails that you can tap through. By default, this setting is set to false.


In Windows 7, when you hover over the Firefox taskbar icon, you’re presented with a popup that shows a thumbnail preview of all the tabs you have open. If you like to have a lot of open tabs, this list can get pretty big and wieldy. Set it to 1 to minimize its intrusion, or whatever value you prefer. By default, this setting is set to 20.



firefox about:config

Do you hate having an X (the close tab button) on every single open tab in Firefox? Then tweak this setting to your pleasure. Setting it to 0 will only show the X on the currently active tab. Setting it to 2 will not display the X on any tabs at all. Setting it to 3 will remove the X from all of the tabs and create a singular X at the end of the tabs list.

By default, this setting is set to 1.


In a fresh-out-of-the-box Firefox browser, closing the last remaining tab will result in the entire browser closing. Some of you may not like this. Luckily, all you have to do is change this setting to false and you’ll be able to have an open browser without having any open tabs. By default, this setting is set to true.



This tweak is a small one, but some of you may desperately be wanting it. Have you noticed that sometimes the URL bar will truncate the http:// portion? If you want Firefox to stop doing that, then simply change this setting to false. By default, this setting is set to true.



At the end of the tabs list, there’s a small button you can click to show a list of all the currently open tabs. With this setting, you can flip it to true and transform the tab list into a tab grid. You’ll see a grid of thumbnails that show all of the tabs you have open. This is very useful for quickly exiting out of multiple tabs.

firefox about:config


This is probably one of the more unknown tweaks out there, but it’s a most useful one. By default, this setting is set to false.

Do you know of any other awesome Firefox about:config tweaks that people would find useful? Share them with us in the comments!

Image Credit: Shutterstock

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  1. Sibernetica
    May 10, 2012 at 2:35 am

    26. oulove 2009/07/05 14:57 ????Close Tab by Double Click ??????????????????: Firefox: 1.5 – 3.6a1pre(0) 2009/07/06 01:24@oulove, ?????????????????Close tabs cliinckg them twice.Weights 2 KB, does just the one thing.??????????(0)

  2. Putralangit
    May 8, 2012 at 8:09 am

    You should take a look at the Super Drag And Go esnitxeon. Opens links in a new tab with a click-drag-release.Once you try it, you won't believe you did it any other way.

  3. goo le
    January 29, 2012 at 9:09 am

    Thank you for sharing, it is
    very useful and I can use it in firefox, flock and avant 2012  

    • Joel Lee
      January 30, 2012 at 3:41 pm

      No problem. I hope it makes your Mozilla experience better. :)

  4. Yamcsha
    January 26, 2012 at 6:43 pm

    thanks, I like the ctrlTab trick

    • Joel Lee
      January 30, 2012 at 3:41 pm

      I'm glad you found it useful!

      • Carlinha
        May 7, 2012 at 3:16 pm

        There is also a mouse gesture exitosenn for firefox so you can get all the myIE (maxthon) type gestures happening too. Once you get used to it, you'll never want to navigate another way.I get really annoyed when I go to someone else's computer with IE and can't use the middle mouse button to open new windows ..

  5. pravin
    January 25, 2012 at 12:14 pm

    This is really cool. A chrome Copied feature. browser.tabs.closeWindowWithLastTab
    Oh Firefox, Please be You. Chrome is just a hype.

    • Mimi
      May 10, 2012 at 1:36 am

      I can't seem to get this setting to STAY THE WAY I SET IT. I cganhe it, then a couple of restarts later, it's back to false. Very maddening.Any way to lock the setting so Firefox doesn't cganhe it again later?

  6. Krzysiek Drozdowski
    January 25, 2012 at 8:54 am

    browser.urlbar.trimURLs - THANKS A LOT FOR THAT!!! :-))) (Sorry, I had to shout)

    • Joel Lee
      January 25, 2012 at 2:56 pm

      No problem! I'm glad you found it helpful. And shouting is fine with me! :)

  7. Anonymous
    January 25, 2012 at 2:46 am

    just beautiful

  8. Scutterman
    January 24, 2012 at 9:58 pm

    browser.showQuitWarning is one I enabled when FF4 removed the "Save and quit" dialogue. More info on that one:
    browser.ctrlTab.previews seems to be similar to a feature that was added (and removed) during the FF3.x betas

    • Joel Lee
      January 25, 2012 at 2:55 pm

      Thanks for sharing the bit about browser.showQuitWarning. That can definitely be useful.

    • Mantaboo
      February 24, 2012 at 10:42 pm

       That is the very first thing I do after a fresh firefox install since I almost always have 3+ tabs open at all times.