Hi Bina,
Thank you for using Syncfusion products.
Deleting the SelectedRecords in GGC parent table is working fine in our side.
Please refer the sample in the below link which illustrates the above.
http://help.syncfusion.com/support/samples/Grid.Windows/7.4.0.20/F93843.zipPlease let me know if you have any further concerns.
Regards,
Christopher K.