Sorry, there are no options for that. And I have never seen an add-on which adds a feature like that to Firefox.

pref("general.config.filename", "mozilla.cfg");
pref("general.config.obscure_value", 0);

defaultPref();	// set new default value
pref();		// set pref, allow changes in current session
lockPref();	// lock pref, disallow changes

Locking the tools menu wouldn't help if they know about modifying related prefs directly. There is also the new about:preferences page and the about:addons page to modify extension settings. How old are those kids? ---- You can use a mozilla.cfg file in the Firefox program folder to lock prefs or specify new (default) values. For proxy settings this wouldn't be that difficult. *http://kb.mozillazine.org/network.proxy.type *http://kb.mozillazine.org/network.proxy.%28protocol%29 *http://kb.mozillazine.org/network.proxy.%28protocol%29_port Place a local-settings.js file in the defaults\pref folder where also the channel-prefs.js file is located to specify using mozilla.cfg. pref("general.config.filename", "mozilla.cfg"); pref("general.config.obscure_value", 0); These functions can be used in the mozilla.cfg file: defaultPref(); // set new default value pref(); // set pref, allow changes in current session lockPref(); // lock pref, disallow changes See: *http://kb.mozillazine.org/Locking_preferences See also: *CCK2 Wizard: https://addons.mozilla.org/firefox/addon/cck2wizard/