<?xml version="1.0"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        xmlns:nc="http://home.netscape.com/NC-rdf#"
        title="insertBefore - Weirdness"
        onload="var atab = document.createElement('tab'); atab.setAttribute('label','new'); document.getElementById('tabs-id').insertBefore(atab,document.getElementById('tabs-id').lastChild);" >
<tabbox>
 <tabs id="tabs-id">
  <tab label="foo" />
  <tab label="bar" />
 </tabs>
 <tabpanels>
  <tabpanel>
   <vbox>
    <label value="foo"/>
   </vbox>
  </tabpanel>
  <tabpanel>
   <vbox>
    <label value="bar"/>
   </vbox>
  </tabpanel>
 </tabpanels>
</tabbox>
</window>