docs: @OverrideOnDemand
    @Nullable
    protected ICommonsMap <String, String> validateCustomInputParameters (@Nonnull final WPECTYPE aWPEC,
                                                                          @Nullable final DATATYPE aSelectedObject,
                                                                          @Nonnull final FormErrorList aFormErrors,
                                                                          @Nonnull final EWebPageFormAction eFormAction)
    {
      return null;
    }