Here is code that will remove selected records from a particular child table in a button handler.
private void button1_Click(object sender, System.EventArgs e)
{
//delete any selection in the child table
SelectedRecordsCollection records = this.gridGroupingControl1.GetTable("ChildTable").SelectedRecords;
if(records.Count > 0)
{
foreach(SelectedRecord r in records)
r.Record.Delete();
}
}
Here is a link to a sample using this code.
http://www.syncfusion.com/Support/user/uploads/GGC_Nested_80aeba9c.zip