rem: this.pref = Components.classes["@mozilla.org/preferences;1"].getService(Components.interfaces.nsIPref); 
add: this.pref = Components.classes["@mozilla.org/preferences-service;1"].getService(Components.interfaces.nsIPrefService).getBranch(null); 
context:     onload:      function ()        {          try             {              this.pref = Components.classes["@mozilla.org/preferences;1"].getService(Components.interfaces.nsIPref);              this.chromeRegistry = Components.classes["@mozilla.org/chrome/chrome-registry;1"].getService(Components.interfaces.nsIXULChromeRegistry);              this.observerService = Components.classes["@mozilla.org/observer-service;1"].getService(Components.interfaces.nsIObserverService);            }          catch(e)             {              dump("*** Failed to create prefs object\n");              return;            }        },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/c5cf4cc2ac34c567e38a272d91bc38772e3475bc/nsPrefWindow.js/clean/suite/common/pref/nsPrefWindow.js