vStack.addMember(backButton);
IButton aboveMiddleButton = new IButton("Above Middle");
aboveMiddleButton.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
dragWidget.moveAbove(middleLabel);
}
});
vStack.addMember(aboveMiddleButton);
IButton belowMiddleButton = new IButton("Below Middle");