    if (invalid) {
        sb.appendHtmlConstant("&nbsp;&lt;span style='color:red;'&gt;");
        sb.append(errorMessage);
        sb.appendHtmlConstant("&lt;/span&gt;");
      }
    }

    @Override
    protected void onEnterKeyDown(Context context, Element parent, String value,
        NativeEvent event, ValueUpdater&lt;String&gt; valueUpdater) {
      Element target = event.getEventTarget().cast();
      if (getInputElement(parent).isOrHasChild(target)) {
        finishEditing(parent, value, context.get