rem: var pbi = gPrefService.QueryInterface(Components.interfaces.nsIPrefBranchInternal); pbi.removeObserver(this.promptDomain, this); 
add: gPrefService.removeObserver(this.promptDomain, this); 
context:   shutdown: function ()  {    var pbi = gPrefService.QueryInterface(Components.interfaces.nsIPrefBranchInternal);    pbi.removeObserver(this.promptDomain, this);  },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/8395/db810767a394be66b9097a7414e21612b09db75b/browser.js/buggy/browser/base/content/browser.js