title: JavaFX put RadioButtons into GridPane
body: <p>I have the following piece of code:</p>
  
  <pre><code>GridPane gp = new GridPane();
  
  // filling GridPane with other nodes...
  
  RadioButton maschio = new RadioButton("M");
  RadioButton femmina = new RadioButton("F");
  final ToggleGroup tg = new ToggleGroup();
  maschio.setToggleGroup(tg);
  femmina.setToggleGroup(tg);
  gp.add(tg, 1, 3);
  </code></pre>
  
  <p>I got an error on the last line saying: <code>ToggleGroup cannot be converted to Node</code>.</p>
  
  <p>What can I do? I also tried with <code>Vbox, Hbox</code> but it didn't work.
  Tried to Google but didn't find the solution. Any suggestions?</p>