public void startup(Display display, Map<String, String> properties) throws Exception {
BXMLSerializer bxmlSerializer = new BXMLSerializer();
window = (Window) bxmlSerializer.readObject(Pivot721.class, "pivot_721.bxml");
// force fill into button renderer, but only in some buttons ...
ButtonDataRenderer filledButtonDataRenderer = new ButtonDataRenderer();
filledButtonDataRenderer.setFillIcon(true);
PushButton button3 = (PushButton) bxmlSerializer.getNamespace().get("button3");
// ((ButtonDataRenderer)button3.getDataRenderer()).setFillIcon(true); // ok, but note that all buttons share a common renderer instance
button3.setDataRenderer(filledButtonDataRenderer); // set/use the customized renderer instance
PushButton button4 = (PushButton) bxmlSerializer.getNamespace().get("button4");
button4.setDataRenderer(filledButtonDataRenderer); // set/use the customized renderer instance