Key(), valueUpdater);
      } else {
        super.onEnterKeyDown(context, parent, value, event, valueUpdater);
      }
    }
  }

  /**
   * The ViewData used by {@link ValidatableInputCell}.
   */
  private static class ValidationData {
    private boolean invalid;
    private String value;

    public String getValue() {
      return value;
    }

    public boolean isInvalid() {
      return invalid;
    }

    public void setInvalid(boolean invalid) {
      this.invalid = invalid;
    }

    public voi