if (url && url.toLowerCase().indexOf("javascript:") >= 0) return 'current';
var mw = Components.classes["@mozilla.org/appshell/window-mediator;1"].getService(Components.interfaces.nsIWindowMediator).getMostRecentWindow("navigator:browser");
var prefs = Components.classes["@mozilla.org/preferences-service;1"].getService(Components.interfaces.nsIPrefBranch);
if (where != 'current')
return where;
else if (prefs.getBoolPref("extensions.stm.openInBlankTab")) {
if (mw.gBrowser.currentURI.spec == 'about:blank' && !mw.gBrowser.selectedTab.getAttribute("busy"))