String event = arg("source");
  NodeInfo node = argObj("node");
  WindowContext context = argObj("windowContext");
  
  log.debug("event received: " + event);

  if ( node != null )
  {
    String nodeType = node.getType();
    log.debug("node type = " + nodeType);
    if ( "helpitem".equals(nodeType) )
    {
       String itemName = node.getText();
       log.debug("itemName: " + itemName + " clicked");
       
       DB db = context.get("db");
       DB.Result items = db.execute("help '" + itemName + "'");
       if ( !items.isEmpty() )
       {
          HashObject item = items.first();
          ((Text)context.get("/No Topic Selected")).setText(itemName);
          TextArea helpText = context.get("/helpText");
          TextArea exampleText = context.get("/exampleText");
          helpText.setText(item.get("description"));
          helpText.setCaretPosition(0);
          exampleText.setText(item.get("example"));
          exampleText.setCaretPosition(0);
       }
    }
  }
  else if ( event == "Search MySQL" )
  {
    String query = ((Text)context.get("/No Topic Selected")).getText();
    query = "No Topic Selected".equals(query) ? "" : query.replace(" ", "+");
    
    BareBonesBrowserLaunch.openURL("http://dev.mysql.com/doc/mysql/search.php?version=5.1&q=" + query + "&lang=en");
  }
  else if ( event == "Close" )
  {
     Dialog d = context.get("/");
     d.dispose();
  }