Hi Ivan,
You could obtain the KB article 'to conditionally hide the plus minus button when there is no child records to show up' from the following link:
http://www.syncfusion.com/support/kb/721/How-to-hide-the-ChildTable-that-doesnSample mentioned in the kb can be obtained from the following link:
http://help.syncfusion.com/samples/kb/grid.windows/GGCHideEmptyChildTable/HideEmptyChildTables.zipPlease let me know if you have any queries.
Regards,
Jisha