TYPO3 Core

Hello guys,

maybe you can fix this buggy wizard ;)

1. Table "A" is in relation with table "B" via a MM-table.
2. TCA is configured to list the relation as a side-by-side field:
   

   'config'  => [
       'type'          => 'select',
       'renderType'    => 'selectMultipleSideBySide',
       'foreign_table' => 'tx_myextname_domain_model_b',
       'MM'            => 'tx_myextname_a_col_mm',
       'size'          => 10,
       'autoSizeMax'   => 30,
       'maxitems'      => 9999,
       'multiple'      => 0,
       'wizards'       => [
           '_PADDING'  => 1,
           '_VERTICAL' => 1,
           'add'       => [
               'module' => [
                   'name' => 'wizard_add',
               ],
               'type'   => 'script',
               'title'  => 'Create new',
               'icon'   => 'EXT:backend/Resources/Public/Images/FormFieldWizard/wizard_add.gif',
               'params' => [
                   'table'    => 'tx_myextname_domain_model_b',
                   'pid'      => '###CURRENT_PID###',
                   'setValue' => 'prepend'
               ]
           ]
       ]
   ]
   

Expected behaviour:
When clicking on "add"-icon and saving a newly generated item of B, then it should prepended to the list of related items.

Actual behaviour:
All related items are going to be deleted except one and the newly generated item.

Thanks 4 help!
Greetings :)