@Test
public void testReplaceChild() throws Exception {

  XulButton btn = (XulButton) hbox.getElementByXPath( "button" );
  XulCheckbox check = (XulCheckbox) hbox.getDocument().createElement( "checkbox" );
  hbox.replaceChild( btn, check );
  XulCheckbox check2 = (XulCheckbox) hbox.getDocument().getElementByXPath( "/window/hbox/checkbox" );
  assertNotNull( check2 );
}