private void hideError() {
DOM.setStyleAttribute(errorLine.getElement(), "visibility", "hidden");
}
private void createUsernameBox() {
username = new NpTextBox();
username.setVisibleLength(25);
username.addKeyPressHandler(new KeyPressHandler() {
@Override
public void onKeyPress(final KeyPressEvent event) {
if (event.getNativeEvent().getKeyCode() == KeyCodes.KEY_ENTER) {