Hi Jens
Thanks for contacting Syncfusion support,
We will implement your requirement as a custom Sample by considering the following criteria
1.Detail grid dataSource will change based on the selected parent grid row
2.Apply the CRUD operation for your detail grid.
Note: We could see that you have not enabled the columns for grids. CRUD will be applied based on the primary key columns. So to enable the CRUD operation, include the columns.
If this does not suit the implementation, share the precise details.
Regards,
Isuriya R