In addition to filling the MasterComponent property, you need to fill the DataRelation property of the detail table. This relation is used to select detail data only for specific rows of the master table. If no relation is specified, all records from the detail table's detail data source will be output for each row of the master table's master data source.

The relation isdataYou can select using the table editor.

It is created between a master data source and a detail data source and selected between relations where the detail data source is the child data source.