There are many hidden preferences in Firefox but no comprehensive documentation, much less French. This is normal as this represents a huge amount of work and in addition, many of these preferences have no reason to be changed therefore be known. The purpose of this article is to present some preferences that may interest you.

To understand this article, you must know Change advanced Firefox preferences.

firefox warning

Determines the type of updates you want to follow (not working before Firefox 1.5).

Type: String

Values: – release: stable releases, beta versions incluses.- correcting security flaws: each beta, and release candidate versions stables.- nightly: every nightly. A nightly version is an updated version every day but with NO guarantee stabilité.- default: no update search. For example, this is the value used when you compile yourself Firefox.


Type: boolean

Values: – True (default on Mac OSX): When you switch the tab in the panel of tools / preferences, the window changes tall with a fondu.- effect False (default on other OS): No animation.

Note: Firefox 1.5 and later only.


Determines the action of a click of the middle mouse button in a content area. It is preferably derived from a middlemouse.paste (see below), which handles the click in a field texte.Type: booléenValeurs: – True: Copies the contents of the clipboard into the bar address. (default on Linux / Unix) .- False: Nothing special. (default on other platforms).


Determines the behavior of a click on the middle button of the mouse over a bar défilement.Type: booléenValeurs: – True: the Centre for the page at the click location. (default on Linux / Unix) .- False: Does nothing. (default in other platforms) .Note: Other articles with other hidden preferences are to come;)