gecko-dev/layout/reftests/native-theme/470711-1.xul

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>

<window id="window470711"
        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <tabbox>
    <tabs>
      <tab label="One"/>
      <tab label="Two" style="padding: 0"/>
      <tab label="Three" style="display: none"/>
    </tabs>
    <tabpanels>
       <label value="One"/>
       <label value="Two"/>
       <label value="Three"/>
    </tabpanels>
  </tabbox>
</window>