As I’ve mentioned before, Firefox is highly customizable. You can add themes, extensions and plug-ins to add new features to your browser. But there are lots of configuration options that you can change as well. I am not just talking about those that you can get to via the Tools, Options…menu. Firefox has a ‘control panel’ of sorts, called about:config. To access, simply open a new tab and in the address bar type about:config.But wait, there is another and ‘easier’ way to get tot this ‘control panel’. It is the AboutConfig extension, once installed you can add a button to your toolbar (right click in a blank area on your toolbar and select ‘Customize…”, find the about:config icon and drag it on to the toolbar). Now you are asking “Oh humble Guru, if I can just type ‘about:config’ in the address bar, why do I need this extension?” Lots of reason, no need to open a new tab, nothing to type, but the best reason…it puts your about:config info in a new window.

This is useful when you are reading directions on changing settings in about:config. Instead of having to flip between tabs, you can make your Firefox smaller (than full screen) and be able to the directions and your about:config at the same time.
To change a setting, highlight the preference you want and then double-click. Note on ‘boolean’ type preferences, double-clicking will change the value from ‘false’ to ‘true’ or from ‘true’ to ‘false’. For ‘integer’ and ‘string’ type preferences, a popup-box will allow you to enter the settings. Preferences in BOLD have been changed from default (user set). While changes are saved as soon as you double-click on a ‘boolean’ or click ‘ok’ on ‘integer’ and ‘string’ type preferences, you can restore a preference to its default by right-clicking and select ‘reset’ from the context menu.

Works with Firefox 1.5. Want to know more about the standard preferences in about:config? Take a look at the mozillaZine Wiki article, about:config entries.