Hi Tayfun,
Thank you for your interest in Syncfusion product.
The GridGroupingControl has an event called SourceListListChangedCompleted, which will fire when the table occur any changes.
The property called ListChangedType in the event will be refered and if a new row is added, the property will be assigned as ItemAdded.
So, this contion will be fired when a new row is created.
Please refer the below sample for detail:
AddingRowsEventSampleLet me know if you have any queries.
Regards,
Nirmal