code: private void addFlatSelectExample() {
  		add(new WHeading(HeadingLevel.H3, "WRadioButtonSelect with flat layout"));
  		add(new ExplanatoryText("Setting the layout to FLAT will make the radio buttons be rendered in a horizontal line. They will wrap when they"
  				+ " reach the edge of the parent container."));
  		final WRadioButtonSelect select = new WRadioButtonSelect("australian_state");
  		select.setButtonLayout(WRadioButtonSelect.LAYOUT_FLAT);
  		add(new WLabel("Flat selection", select));
  		add(select);
  	}
docs: adds a WRadioButtonSelect with LAYOUT_FLAT.