rem: if (window.frames["content"].location != "about:blank") window.frames["content"].location = "about:blank"; 
add: if (window.frames["content"].location.href != "about:blank") window.frames["content"].location.href = "about:blank"; 
context: function ClearPrintEnginePane(){  if (window.frames["content"].location != "about:blank")      window.frames["content"].location = "about:blank";}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/cddca7b1217f1f1a10c371a975c199b3efbaa9cc/msgPrintEngine.js/clean/mailnews/base/resources/content/msgPrintEngine.js