<?xml version="1.0"?>

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

<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" onload="boom();">

<script type="text/javascript">
// <![CDATA[

var XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";

function boom()
{
  var lb = document.getElementById("lb");
  var firstli = document.getElementById("firstli");
  lb.appendChild(document.createElementNS(XUL_NS, "hbox"));
  lb.appendChild(document.createElementNS(XUL_NS, "listitem"));
  firstli.style.display = "none";

  // Flush layout.
  document.getBoxObjectFor(document.documentElement).height;

  lb.removeChild(firstli);
}

// ]]>
</script>

<listbox id="lb"><listitem id="firstli"/></listbox>

</window>