DataGrid supports Filtering of hierarchical data. When a child element is visible, all its ancestors should also be visible.
The filter applied to the DataGrid is [ 'FirstName', 'contains Michael or contains Nancy' ], which means it will display all records with 'FirstName' equal to 'Michael' or 'Nancy'. As 'Michael' and 'Nancy' are sub-records of 'Andrew' and 'Steven', they are displayed in the view.