Firefox Tweak Guide

[Page 4] Firefox Settings

This section covers all the main Firefox settings which can be accessed under the Firefox Options menu screens. Before you do any customization or tweaking of Firefox, you will need to understand what all of these settings do, and make sure that they are configured correctly. The main settings can be found by clicking the large orange Firefox button at the top left of the browser window, and selecting Options. Each section of the Options window is covered in detail below, with recommendations where relevant.

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New to Firefox 15, you can enable Incontent Preferences, which allows you to view the Firefox Options within a browser tab as opposed to a separate window. This feature is disabled by default, so you will need to set the browser.preferences.InContent preference to True in About:Config in order to use it - see the Advanced Tweaking section for details.


When Firefox starts: You can configure Firefox to do one of the following whenever it starts: 'Show my home page' will automatically load up the website which you have entered in the Home Page box; 'Show a blank page' will simply start Firefox with a blank page; and the 'Show my windows and tabs from last time' option' will use Firefox's Session Restore feature to restore all your open browser windows/tabs to exactly the way they were when you last closed Firefox. Select the option you prefer, but obviously the more page(s) Firefox has to load and/or the more content-rich the page(s) are when starting up, the slower startup may be.

New to Firefox 8.0, the 'Don't load tabs until selected' option has been added just below the 'When Firefox Starts' box. This option is only available when 'Show my windows and tabs from last time' is selected in the drop-down box, and if ticked, whenever you restore your previous session, only the content in the foremost tab will be loaded to speed up startup time; the content in the other tabs will load once you switch to them.

Home Page: If you've chosen the 'Show my home page' option under the 'When Firefox Starts' setting (see above), you can choose the page which appears whenever you open up Firefox. You can either manually enter a web address in the 'Home Page' box; if you want to set the page you are currently viewing as the home page click the 'Use Current Page' button; or you can choose a page from your Bookmarks. You can set multiple homepages as well, each opening up in a separate tab when you launch Firefox or click the Home button - either click 'Use Bookmarks' and select a folder, or open the relevant pages as tabs then click the 'Use Current Pages' button.

New to Firefox 13.0, a new default Firefox Home Page is available which displays a Google search box, and below it a range of links to key Firefox features including Downloads, Bookmarks, HIstory, Add-Ons, Sync, Settings and Restore Previous Session. You can access this page at any time by typing 'About:Home' (without quotes) in the address bar, or by clicking the 'Restore to Default' button here to set it as your home page.

Downloads: When Firefox begins downloading a file using its built-in download manager, and the 'Show the Downloads window when downloading a file' box is ticked, you will see the Downloads window appear. This is useful as it shows you the progress of the file download, and gives you the option of cancelling or pausing the download at any time, hence I recommend you tick this option. You can also tick the 'Close it when all downloads are finished' box so that when all downloads are completed the Downloads window automatically closes. See the 'Downloads Window' area of the Features, Tips and Tricks section for more details of its functionality.

Save Files To: Every time you choose to download a file from the Internet with Firefox, it will be saved to a particular location on your drive. You can either select to have Firefox 'Always ask me where to save files' for each file, or as recommended, select a fixed download folder under the 'Save files to' box. Note: I don't recommend saving files to the Windows Desktop, as this can increase Memory usage in Windows and increase startup times.

Add-ons: This section allows you to access the Add-ons Manager window by clicking the 'Manage Add-ons button'. Add-ons provide a range of custom functionality to Firefox, and are an important feature. See the 'Add-ons Manager' area of the Features, Tips and Tricks section for full details of its functionality, as well as the Add-Ons section of this guide for recommended Add-ons.


Open new windows in a tab instead: This setting essentially controls whether you use tabbed browsing or not. Whenever you click a web link on a page, if this option is unticked, the link will open as a new window in a separate instance of Firefox; if it is ticked, any new pages launched will open as a new tab within an existing instance of Firefox. I strongly recommend that this option be ticked to take advantage of tabbed browsing in Firefox, and prevent lots of instances of Firefox running. See also the preference in the Advanced Tweaking section for more ways to alter this setting.

Warn me when closing multiple tabs: If ticked, this option raises a warning when you try to close a Firefox window containing multiple open tabs. If you're the forgetful type, or if you're used to seeing each page open in a separate window, you might want to tick this so you don't close down Firefox when you simply intended to close a single tab. Otherwise for those familiar with Firefox I suggest unticking it for quicker closing of Firefox windows.

Warn me when opening multiple tabs might slow down Firefox: If ticked, Firefox will warn you if you are likely to cause slowdowns or problems in Firefox by launching too many tabs at once. For the most part this depends on how much memory your system has available. I suggest ticking it to begin with, as you shouldn't be warned unless you're truly getting to the point where there are too many tabs opening up and Firefox is using too much memory to remain responsive. If you reach such a point, the best option is to close Firefox altogether and re-open it with fewer tabs open at any one time.

Always show the tab bar: If ticked, this option forces the tab bar at the top of the Firefox viewable browser area to remain shown, even if only one page is currently open. If unticked, and you only have one tab open, then no tab bar will be shown. If more than one tab is open at any time, this option has no impact - the tab bar will be displayed regardless.

New to Firefox 23, This setting has been removed from the Options and enabled by default now. The browser.tabs.autoHide setting in About:Config controls this feature, but is now also non-functional, which means this option cannot be changed.

When I open a link in a new tab, switch to it immediately: This option determines whether pages launched in a new tab are shown in the foreground or the background. When you open a new tab from a link on the current page, if this option is unticked any new tabs opened will be in the background, not affecting the tab you're currently viewing. If ticked, your view will automatically switch to the most recently opened tab, effectively forcing all other tabs to the background.

Show tab previews in the Windows taskbar: New to Firefox 4.0, if ticked this option allows Firefox to display separate thumbnail previews for every open tab in the Windows Taskbar on Windows Vista/7 systems. If unticked, only the foremost tab will be shown in the thumbnail preview when your mouse hovers over the Firefox icon in the Windows Taskbar.


Block pop-up windows: This option is designed to block 'pop-up' windows, which are separate browser windows/tabs which typically open up by themselves when you open a web page, or click on certain parts of a site. They are most commonly used for advertising, and can vary in frequency, size and location. On websites for which a pop-up window has been blocked, by Firefox will raise a yellow warning bar stating that 'Firefox prevented this site from opening a pop-up window'. You can click the Options button at the far right of this prompt bar to determine whether you want to allow this particular site to display pop-ups, or whether you don't want this warning bar displayed again for any site with blocked pop-ups. Bear in mind that some sites have legitimate popup windows, and hence may not work correctly if you block their pop-ups. Click the 'Exceptions' button and enter the names of trusted sites you want to allow popups for in the format, then click the Allow button to add each one of them.

Some popups are script-based events triggered by clicking on certain parts of a site, and are specially designed to circumvent popup blocking, so you may still see pop-ups despite the use of the pop-up blocker option. You can only block such popups if you disable Javascript (see further below); change the privacy.popups.disable_from_plugins and preferences as covered in the Advanced Tweaking section; or install a script-blocking add-on like NoScript, covered in the Add-ons section. Also keep in mind that any spyware/adware resident on your PC may launch browser popups regardless of the site you visit or your browser settings, so make sure you thoroughly scan your system for malicious software. If you've disabled the Firefox pop-up warning prompt bar and want to re-enable it, see the privacy.popups.showBrowserMessage preference in the Advanced Tweaking section.

Load images automatically: Ticking this option allows images to be automatically loaded up with web pages - and most every web page contains a range of images, even if only for formatting purposes. If however you want to choose to disable or allow images specifically on a site-by-site basis, click the Exceptions button and manually select websites which you can then permanently Block or Allow images from individually. Just remember that many graphical annoyances such as advertisements are actually Flash files or scripts, and not simple images, and hence this setting doesn't affect them. See the Add-ons and Advanced Tweaking sections of this guide for details of various methods you can use to block different types of ads and scripts if they annoy you.

New to Firefox 23, This setting has been removed from the Options and enabled by default now. To adjust it, you will need to go to your About:Config preferences and set permissions.default.image to 1 for enabled, or 2 for disabled. See the Advanced Tweaking section of the guide for details.

Enable Javascript: Many sites use Javascript to produce certain effects, or allow a range of functionality. For example, YouTube requires that Javascript be enabled to view videos. For this reason I recommend you leave this option ticked, as many websites will not display or function correctly without it. Click the Advanced button to see the Javascript-based effects which you can enable or disable. I personally have all the functions listed unticked - this means all websites display correctly, but they can't try any fancy tricks like resizing windows on me or changing menus. If you want to be more selective about which sites you allow Javascript on, see the NoScript extension in the Add-ons section.

New to Firefox 23, This setting has been removed from the Options and enabled by default now. To adjust it, you will need to go to your About:Config preferences and set javascript.enabled to True for enabled, or False for disabled. See the Advanced Tweaking section of the guide for details.

Fonts & Colors: Here you can customize the fonts, colors and styles used for various elements of web pages displayed in Firefox. For example, if you want all Sans-serif text on web pages to be Arial, click the Advanced button then select that font under the 'Sans-serif' box. You can even set a minimum font size. You can also change the colors used for various text and links on web pages by clicking the Colors button. The important thing to understand however is that most web pages already specify their default fonts and the styles of various elements like hyperlinks, background and text colors, etc. Therefore changing the settings here will typically have no visible impact. If you want to ensure that your selections here override the default web page options, you have to untick the relevant 'Allow pages to choose their own' boxes in the Advanced and/or Colors sections, then refresh the page to see your choice of colors and fonts implemented.

If you want to increase the font size across all web pages, then click the Advanced button, then select a font size in the 'Minimum font size' box. The larger you make this value, the larger the text displayed on all web pages.

If you want to change the text rendering method in Firefox - as some people may not like the default text rendering method employed - then see the 'Use hardware acceleration when available' option under the Advanced section of the next page.

Languages: Some web pages offer different language versions which display by default when you view them. Add/Select which language you want pages to display with by default if they offer such an option. Remember that if you want a different language version of Firefox itself, for correct spell checking for example, you need to download and install the appropriate language version of Firefox to begin with - See The Basics section of this guide. You can also download different dictionary and language packs - see the Add-ons section for details.


Content Type: The first time you click on certain types of files you will be asked how you want Firefox to handle such links in the future - i.e. whether you want Firefox to always prompt you to decide; to automatically save them to your drive (if relevant); or to automatically open them, and if so, with which particular application. You may also be prompted to select whether you want your choice to become the default behavior for that particular file type when you first encounter it when browsing. Your choices are stored in this section of the Options, and you can manually come here and adjust them at any time. All the main file types and protocols that your browser has accessed so far are listed under the 'Content Type' column, and when you select the relevant content type, the behavior in the Action column becomes a drop-down menu you can use to alter as you see fit.

I recommend that where possible you change the behavior for archival file formats such as .zip or .rar, and online document formats such as .pdf and .docx to 'Save File' as the default, as otherwise Firefox may try to automatically open these file types. Adobe PDF documents for example can take quite a while to load up if Firefox attempts to open them within the browser instead of downloading them. Also, make sure to set your default Save directory - found under the General tab of the Options window - to somewhere other than the Windows Desktop for memory usage reasons. Note that the handling of email links can be set by altering the mailto protocol here.

The next page continues the Firefox setting descriptions.