gecko/toolkit/obsolete/content/globalOverlay.xul

<?xml version="1.0"?> 

<overlay id="globalOverlay"
		 xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

  <script type="application/javascript" src="chrome://global/content/globalOverlay.js"/>
  <script type="application/javascript"><![CDATA[

    function FillInTooltip ( tipElement )
    {
      var retVal = false;
      var textNode = document.getElementById("TOOLTIP-tooltipText");
      if (textNode) {
        while (textNode.hasChildNodes())
          textNode.removeChild(textNode.firstChild);
        var tipText = tipElement.getAttribute("tooltiptext");
        if (tipText) {
          var node = document.createTextNode(tipText);
          textNode.appendChild(node);
          retVal = true;
        }
      }
      return retVal;
    }

  ]]></script>

  <popupset id="aTooltipSet">
    <tooltip id="aTooltip" class="tooltip" onpopupshowing="return FillInTooltip(document.tooltipNode);">
      <label id="TOOLTIP-tooltipText" class="tooltip-label" flex="1"/>
    </tooltip>
  </popupset>

</overlay>