title: How to understand and use `<fx:root>` , in JavaFX?
body: <p>It says tag <code>fx:root</code> has been added to javafx 2.2, but I don't understand how to use it, although with this sample: <a href="http://docs.oracle.com/javafx/2/fxml_get_started/whats_new2.htm" rel="noreferrer">http://docs.oracle.com/javafx/2/fxml_get_started/whats_new2.htm</a></p>
  
  <p><strong>main.xml</strong></p>
  
  <pre><code>&lt;?import javafx.scene.layout.GridPane?&gt;
  &lt;GridPane fx:controller="sample.Controller"
            xmlns:fx="http://javafx.com/fxml" alignment="center" hgap="10" vgap="10"&gt;
      &lt;fx:include fx:id="editorPane" source="editor.fxml"/&gt;
  &lt;/GridPane&gt;
  </code></pre>
  
  <p><strong>editor.fxml</strong> without <code>fx:root</code>:</p>
  
  <pre><code>&lt;?import javafx.scene.control.TextArea?&gt;
  &lt;TextArea fx:id="editor" prefWidth="500" prefHeight="400" 
     fx:controller="sample.EditorController"
     xmlns:fx="http://javafx.com/fxml"/&gt;
  </code></pre>
  
  <p><strong>editor.fxml</strong> with <code>fx:root</code>:</p>
  
  <pre><code>&lt;fx:root type="javafx.scene.control.TextArea"
       fx:id="editor" prefWidth="500" prefHeight="400"
       fx:controller="sample.EditorController"
       xmlns:fx="http://javafx.com/fxml"/&gt;
  </code></pre>
  
  <p>Actually, I can't find any difference for the two kinds of code. Do I miss anything?</p>