rem: var pbi = gPref.QueryInterface(Components.interfaces.nsIPrefBranchInternal); 
add: var pbi = gPref.QueryInterface(Components.interfaces.nsIPrefBranch2); 
context: function addPrefListener(observer, prefStr){    try {        if (gPref == null) {            var prefService = Components.classes["@mozilla.org/preferences-service;1"]                                        .getService(Components.interfaces.nsIPrefService);            gPref = prefService.getBranch(null);        }        var pbi = gPref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);        pbi.addObserver(prefStr, observer, false);    } catch(ex) {        dump("Failed to observe prefs: " + ex + "\n");    }}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/4b68fa447a8983137138e2d20be274a6c51fc137/nsAxSecurityPolicy.js/clean/embedding/browser/activex/src/plugin/nsAxSecurityPolicy.js