<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        xmlns:html="http://www.w3.org/1999/xhtml">
        class="reftest-wait">
  <script type="text/javascript"><![CDATA[
    function run() {
      const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
      const HTML_NS = "http://www.w3.org/1999/xhtml";
      var span = document.getElementsByTagNameNS(HTML_NS, "span")[0];
      span.parentNode.removeChild(span);
      setTimeout(finish, 0);
    }
    function finish() {
      document.documentElement.removeAttribute("class");
    }
    function load(event) {
      setTimeout(run, 0);
    }
    window.addEventListener("load", load, false);
  ]]></script>
  <vbox flex="1">
    <html:span style="display:inline" flex="1" /> <!-- causes block wrapping -->
    <box flex="1" />
    <label value="hello world" />
  </vbox>
</window>
