Are you using nested tables? If so, the code grid.Table.SelectedRecords only gets the selected records from the parent Table. If you have nested tables, then you would also need to query the Table.SelectedRecords collection for each nested table, maybe using code such as:
gridGroupingControl1.GetTable("ChildRelatedTableName").SelectedRecords
Here is a sample that works for me using teh 6.1 code base to show the underlying data for selected records. Does it work for you? What is different about what you are doing?
WindowsApplication24_4.zip