@Override
public void onClick(ClickEvent event) {
long elapseRetry = System.currentTimeMillis();
GWT.log("[TestButtonPanel:2nd-con>NEXT>RETRY:" +
"onClick()] start");
FourTypes fourTypes = new FourTypes();
fourTypes.showTopPage();
Window.scrollTo(0, 0);
GWT.log("[TestButtonPanel:2nd-con>NEXT>RETRY:" +
"onClick()] end: " +
(System.currentTimeMillis() - elapseRetry) +
"mSec.");