TableDescriptor Relations collection

Hi, I''m using the GGC and trying to define a Relation. When the DataSource of the grid is not set or null, I get the following exception on the application start: An unhandled exception of type ''System.InvalidOperationException'' occurred in syncfusion.grouping.base.dll Additional information: Possible incorrect RelationDescriptor.ChildTableName for Relation Detail. Engine.SourceListSet[Detail] returned null. Did you forget to call Engine.SourceListSet.Add(new SourceListSetEntry(Detail, list) or did you specify a wrong ChildTableName? However if define the relation after the datasource is populated - it works fine. Please advise. Thank you

It seems that if leave ChildTableName blank and specify MappingName only it works! Thank you