private void open(SimpleUserNode node) {
   if (node != null) {
     IPersist persist = (IPersist) node.getRealObject();
     if (node.getType() == UserNodeType.STYLE_ITEM) {
       EditorUtil.openStyleEditor((Style) persist);
     }
   }
 }
 protected boolean calculateEnabled(SelectionChangedEvent event) {
   IStructuredSelection sel = (IStructuredSelection) event.getSelection();
   if (sel.size() == 0) {
     return false;
   }
   Iterator<SimpleUserNode> nodes = sel.iterator();
   while (nodes.hasNext()) {
     SimpleUserNode node = nodes.next();
     if (node.getType() != UserNodeType.GLOBALS_ITEM) {
       return false;
     }
   }
   return true;
 }