private PushButton createButton(ImageResource icon) {
final PushButton b = new PushButton(new Image(icon));
b.setStylePrimaryName("action-button");
b.addStyleName(_resources.buttonStyles().button());
b.setTabIndex(-1);
b.addMouseDownHandler(new MouseDownHandler() {
@Override
public void onMouseDown(MouseDownEvent event) {
b.setFocus(false);
}