add:  if (boxToShow) boxToShow.setAttribute("hidden", "true"); boxToShow = null; 
context: function hideShowSmtpSettings(smtpServer) {  var noSmtpBox = document.getElementById("noSmtp");  var haveSmtpBox = document.getElementById("haveSmtp");  var boxToHide;  var boxToShow;    if (smtpServer && smtpServer.hostname &&      smtpServer.hostname != "") {    // we have a hostname, so show the static text    boxToShow = haveSmtpBox;    boxToHide = noSmtpBox;  } else {    // no default hostname yet    boxToShow = noSmtpBox;    boxToHide = haveSmtpBox;  }  if (boxToHide)    boxToHide.setAttribute("hidden", "true");  if (boxToShow)    boxToShow.removeAttribute("hidden");}
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/f80eb91f12e685696ef460c94dfb240883d8bbda/aw-server.js/buggy/mailnews/base/prefs/resources/content/aw-server.js