If you have already tried about:config URL then you must be aware of the warning Firefox displays before allowing you to access the config settings. It actually is a risky scenario, so it would be wise to backup Firefox’s configuration data before proceeding. To back up configuration settings, go to Run command and type:
Executing this command brings up the Firefox profiles folder within which you can find another folder with .default extension. From this folder copy file “ user.js” to a safe location. Later on, after we have modified settings, if we have messed up instead of optimizing, this backup copy can be used to restore the settings.
Using about:config URI scheme offers nearly 500 config entries in Firefox 3.0 , a complete list can be found here
You can also create new preferences by pointing Firefox to about:config and selectingNew‘ from the context menu choosing the preference type you want to create. If the value you intend to add is an integer then chose integer as the type of the key, for string values select the string type and for values which can be either true or false, select Boolean type. Apart from creating new, you can also edit existing key/values by selecting the entry and clicking on modify‘ from the context menu in case of string or integer values and toggle‘ in case of Boolean values. Use the filter box to find the entries you are looking for.
Following are some of the known about:config hacks that I am reproducing here for demonstration. ( None of these are verbatim copies )
1. Open search result in a new Tab:
While using the Firefox search bar you may at times want to open the result page in a new Tab so that the page you are currently viewing stays intact.
2. Copy full URL in a single click:
Do you find yourself frequently copying the URL from the location bar of the browser? It can be a bit annoying if you have to drag the mouse to copy the full URL. You can customize Firefox to select the full URL from the location bar by modifying the following entry.
browser.urlbar.clickSelectsAll = True
To do the opposite i.e. allow to copy parts of URL set the preference to false.
browser.urlbar.clickSelectsAll = False
3. Disable auto-complete URL :
4. Modify Tab undo history:
In the first part of this series I gave the shortcut to re-open the last open tab (Ctrl +Shift + T) . What this implies is that the information on open tabs are saved by Firefox and because of this reason there is a limit to the number of tabs you can reopen. You can change the number of recently closed tabs that whose information is saved by modifying the following entry.
5. One button to close them all:
If you want to have one close button to control all opened Tabs, set the value of the following key to 3.
browser.tabs.closeButtons = 3
6. Disable favicon:
If for some reason you want to disable the favicon in location bar and on Tab toggle the value of the following key to false.
browser.chrome.site_icons = False
7. Trim auto-complete URL list:
Finally, if your Location bar has a huge list of auto-complete URLs , it can become annoying. Modify the maxRichResults‘ entry to specify the number of URLs to save in your auto-complete URL list.
browser.urlbar.maxRichResults = 5 (Keeps 5 URLs)
These are some of the about:config hacks that can help you customize Firefox to funtion exactly as you want it to. In the following post we will hack these entries to make Firefox faster and use less memory.