public SplitDropdownButton(Resources res, Element container, ImageResource labelImage) {
BaseResources.Css baseCss = res.baseCss();
Css css = res.dropdownWidgetsCss();
labelButton = new ImageButton2(res, labelImage);
labelButton.getButtonElement().addClassName(css.splitButtonLabel());
container.appendChild(labelButton.getButtonElement());
triggerButton = new ImageButton2(res, res.disclosureArrowDkGreyDown());
triggerButton.getButtonElement().addClassName(css.splitButtonArrow());
container.appendChild(triggerButton.getButtonElement());
}