rem: catch (e) { alert(e); } 
add: catch (e) { } 
context: function isXPInstallEnabled() {  var enabled = false;  var locked = false;  try {    enabled = gPref.getBoolPref("xpinstall.enabled");    if (enabled)      return true;    locked = gPref.prefIsLocked("xpinstall.enabled");  }  catch (e) { alert(e); }  var msgText = getExtensionString(locked ? "xpinstallDisabledMsgLocked" :                                            "xpinstallDisabledMsg");  var buttonLabel = locked ? null : getExtensionString("enableButtonLabel");  var buttonAccesskey = locked ? null : getExtensionString("enableButtonAccesskey");  var notifyData = locked ? null : "addons-enable-xpinstall";  var addonsMsg = document.getElementById("addonsMsg");  addonsMsg.showMessage("chrome://mozapps/skin/extensions/question.png",                        msgText, buttonLabel, buttonAccesskey,                        !locked, notifyData);  return false;}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/524af9eacf08a8d64e6466bee7f49dc87c8f9260/extensions.js/clean/toolkit/mozapps/extensions/content/extensions.js