List of Pale Moon specific about:config preferences

Martin Brinkmann
Nov 11, 2015
Updated • Jun 26, 2017
Internet, Pale Moon

The following article lists known preferences of the Pale Moon web browser that are unique to it which means that they are not found in Firefox.

Our list of Firefox privacy and security preferences has been updated today, and one of the new features of it is a dedicated Pale Moon section.

This article is designed to list these Pale Moon specific preferences, and also to get input from Pale Moon users who may know of other preferences that we are not aware of. These can be preferences unique to Pale Moon, or preferences that Mozilla deprecated in Firefox but are still available in Pale Moon.

How to use these preferences

pale moon unique preferences

Pale Moon users have two options to use the preferences listed below. They may either use about:config to modify them, or add a user.js file to their Pale Moon profile directory to add them this way.

Using about:config

This is without doubt the faster option for most users. Simply load about:config in Pale Moon's address bar and hit enter.

To change a preference search for it using search at the top on the page that opens, and double-click on the preference to either flip its value if it is a Boolean (true or false), or enter a value instead if it is not.

Using user.js

Note: The user.js file has priority over preference changes made in Firefox. If you set preferences using the file, you won't be able to change them permanently in Firefox.

There is no user.js file by default which means that you need to create it. One of the easier ways to go about it is the following:

  • Open about:support in the Pale Moon browser. This loads the Troubleshooting Information page.
  • Click on the show folder button to open the Pale Moon profile folder on the local system.
  • If there is no user.js file in the folder, create a new plain text document in the folder and name it user.js. Make sure it has no other extension besides that (it should not be user.js.txt).
  • Add the preferences you want to modify using the syntax user_pref("preference name", "preference value");

Security and Privacy preferences

// 3201: (v25.6+) disable canvas fingerprinting
user_pref("canvas.poisondata", true);
// 3202: (v25.2+) control HSTS (If editing this in about:config PM needs to be fully closed and then restarted)
// NOTE: This is a trade-off between privacy vs security. HSTS was designed to increase security to stop MiTM attacks but can also
// be misused as a fingerprinting vector, by scrapping previously visited sites. Recommended: security over privacy - but your choice.
user_pref("network.stricttransportsecurity.enabled", true);
// 3203: (v25.0+) controls whether to ignore an expired state of stapled OCSP responses
// If set to true, breaks with RFC6066 (like Firefox) and ignores the fact that stapled OCSP responses may be expired.
// If false (the default) aborts the connection.
user_pref("security.ssl.allow_unsafe_ocsp_response", false);

Other Pale Moon specific preferences

Preference name Value(s) Description
browser.display.ignore_accessibility_theme FALSE Override the use of accessibility colors on web pages.
browser.display.standalone_images.background_color #2E3B41 Change the background color of individual images displayed in the browser
browser.padlock.shown TRUE Defines whether a padlock icon is shown on secure sites. Defines where the padlock icon is shown
1 After the root domain name in the address bar
2 Before the root domain name in the address bar
3 To the right of the address bar
4 In the Status Bar
5 To the right of the Tab Bar
browser.padlock.urlbar_background Address bar shading preference
0 no shading
1 shading for secure sites
2 shading for secure sites and mixed content sites
3 shading for all https sites including broken ones.
browser.sessionstore.exactPos FALSE Defines whether the restored browser session window is displayed at the same location when it was terminated in the last session.
browser.sessionstore.max_concurrent_tabs 3 The number of tabs concurrently restored from a session. Accepted values 1-10
browser.tabs.resize_immediately FALSE Defines whether tabs resize immediately on the Tab Bar when tabs are closed.
browser.urlbar.rss TRUE Defines whether an RSS indicator is displayed in the address bar.
lightweightThemes.animation.enabled FALSE Defines whether animated lightweight themes (Personas) are allowed.
prompts.tab_modal.focusSwitch TRUE Controls whether modal dialogs on web pages switch foxues to the tab the dialog is presented on (e.g. JavaScript alerts).
signon.ignoreAutocomplete TRUE Defines whether autocomplete="off" is ignored by Pale Moon
spellchecker.dictionary.override NULL Sets a preferred language for spellchecking, overides document/element languages. Does not exist by default.


Now You: Know of other preferences not already included on this page? Have something to add?

List of Pale Moon specific about:config preferences
Article Name
List of Pale Moon specific about:config preferences
The guide lists Pale Moon specific preferences that are unique to the browser, or have been deprecated in Firefox.
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  1. Gonzo said on November 17, 2015 at 3:59 am

    As a Linux user (full time as of last month) I really like the site specific useragent override.

    This feature was removed from FF but not Pale Moon. I still haven’t found an add-on that can accomplish this in FF.

  2. bawldiggle said on November 16, 2015 at 2:29 am

    Thank you Martin for this “lead-in” As a user of Palemoon for last 3 years I am still learning
    – stuff I didn’t know existed :)

  3. Ben said on November 12, 2015 at 2:35 pm

    > Note: The user.js file has priority over preference changes made in Firefox. If you set preferences using the file, you won’t be able to change them in Firefox.
    You can still change them in FF, but upon the next restart the values will be overwritten with the ones from user.js.

    1. Pants said on November 13, 2015 at 12:20 am

      Totally agree. That needs rewording Martin – it’s very misleading.

  4. Tom Hawack said on November 12, 2015 at 2:01 pm

    Not to mention that several if not many of the settings optimized for Firefox simply do not exist in Pale Moon, mainly those regarding privacy. No point in adding to a Pale Moon’s user.js settings which do not exist. That is of course the big advantage of Pale Moon when editing the user.js (or directly the about:config settings) concerns optimization and, as far as I know/remember, never privacy concerns. The browser is clean, that’s for sure. if I get fed up of a Firefox reaching the ultimate of inconsistency I’ll switch back to Pale Moon. Not sure yet (other topic).

  5. B said on November 12, 2015 at 1:58 pm

    Hi Martin
    a bit off topic: palemoon still supports the addon BetterPrivacy; but it is no longer available for firefox. apparently “no longer compatible ” but firefox “works on a fix”. do you anything about this?

    1. RodsMine said on November 15, 2015 at 12:20 am

      Apparently, BetterPrivacy is preventing the cache from being cleared (from itself and from FF options) so the author asked Mozilla to disable it for FF42 until he can get it fixed.

    2. Martin Brinkmann said on November 12, 2015 at 7:14 pm

      Hi, unfortunately not.

  6. LimboSlam said on November 12, 2015 at 8:33 am

    In about:config “browser.tabs.onTop” and “browser.allTabs.previews” are deprecated in Firefox and only available through Pale Moon now.

    Oh and “browser.tabs.autoHide.”

  7. Richard Allen said on November 12, 2015 at 2:37 am

    As far as the Pale Moon Commander addon there is a pdf manual available on the same page where the addon can be downloaded from. Bottom of the page under Documentation, it does a pretty good job of explaining the different settings.

    One about:config entry missed: browser.cache.compression_level – which is set at 3 by default in PM. In FF the default is 0. I personally use 0 with the thought that my mechanical hard drive might be a bottleneck. With an ssd I imagine using compression would be a non-issue as far as performance goes. I only use 100 MB of cache anyway because I think I have sufficient bandwidth to make up for the small cache size. I’m also thinking the small cache size will cause the elements in the cache to be replaced more frequently, possibly helping privacy? ;)

    1. Pants said on November 12, 2015 at 9:15 am

      Depending on how you use your browser (I’m not someone who has more than 15-20 tabs open, and very little media if ever), I’m a great believer in not having a disk cache at all.

  8. Pants said on November 12, 2015 at 2:09 am

    I kinda feel the new version announcement has been buried a little under the topic and non PM users may miss it – hopefully the next FF article, Martin can reiterate it.

    Many thanks to Moonchild for his awesomely fast and excellent communication and list – the guy should be a firefighter or something :) Hoping the ghacks and PM forum members can enlighten me to any security/privacy specs that due to deprecation by FF, are now PM unique.

  9. jasray said on November 11, 2015 at 10:46 pm

    Not really preferences, but PaleMoon does have the Add-On “PaleMoon Commander” that has numerous performance tweaks available; however, I have found little about the “ideal” settings in each category. It’s an Add-On that works with other browsers, such as Cyberfox and Firefox. Any clarification about settings by anyone?

    1. Corky said on November 12, 2015 at 1:53 pm

      PaleMoon Commander has a manual that explains what most of the settings do, there’s a link to it at the bottom of the addon page.

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