+ # hack: add partsgroup for first row if it does not exists,
+ # because _remove_billed_or_delivered_rows and _remove_full_delivered_rows
+ # determine fields to handled by existing fields for the first row. If partsgroup
+ # is missing there, for deleted rows the partsgroup_field is not emptied and in
+ # update_delivery_order it will not considered an empty row ...
+ $::form->{partsgroup_1} = '' if !exists $::form->{partsgroup_1};
+