rem: urlBarHist.clearHistory(); dump("Now history should be empty. \n"); 
add: urlBarHist.clearHistory(); dump("Now history should be empty. \n"); 
context: function prefClearUrlbarHistory(){  var button = document.getElementById("ClearUrlBarHistoryButton");  var urlBarHist = nsJSComponentManager.getService("@mozilla.org/browser/urlbarhistory;1",  "nsIUrlbarHistory");  if ( urlBarHist )  {  	urlBarHist.clearHistory();  	dump("Now history should be empty. \n");    button.setAttribute("disabled","true");  }}  
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/bccffbbaba069a33ee67f64aa9643d8302d2ae25/prefutilities.js/buggy/xpfe/components/prefwindow/resources/content/prefutilities.js