@UiHandler(value = { "button1", "button2", "button3", "button4" })
public void onClickEvent(ClickEvent e) {
final Widget w = (Widget) e.getSource();
Transition transition = new Transition(new Quadratic(),
Type.EASE_IN_OUT) {
int initialWidth = w.getElement().getClientWidth()
- WidgetHelper.getBoxModel(w).getPaddingWidthContribution();