add: if (active_languages.selectedIndex == (active_languages_treeroot.childNodes.length - 1)) {  var moveDown = document.getElementById("down"); moveDown.disabled = true; }  if (active_languages_treeroot.childNodes.length > 1) {  var moveUp = document.getElementById("up"); moveUp.disabled = false; }  
context: function MoveDown() {  if (active_languages.selectedItems.length == 1) {    var selected = active_languages.selectedItems[0];    if (selected.nextSibling) {      if (selected.nextSibling.nextSibling) {        selected.parentNode.insertBefore(selected, selected.nextSibling.nextSibling);      }      else {        selected.parentNode.appendChild(selected);      }      active_languages.selectItem(selected);    }  }  UpdateSavePrefString();} //MoveDown
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/89ac376f49d7289abe8751d96543de1e957e7bca/pref-languages.js/buggy/xpfe/components/prefwindow/resources/content/pref-languages.js