Adding a warning when a data source are not populate in a model

Once data elements are read once, adding a new data source has no
effect. A warning that tells that adding a new data source after had no
effect will help to debug. Here is an example. The observe problem was
that no data where send to the database in the postprocess step.
main {
var OPDSource = new IloOplModelSource("OptProd.mod");
var OPDDef = new IloOplModelDefinition(OPDSource);
var OPDCplex1 = new IloCplex();
var OPDModel1 = new IloOplModel(OPDDef,OPDCplex1);
var OPDData = new IloOplDataElements();

//Define data source
var OPDDataSourcePrm = new IloOplDataSource("data1.dat");
var OPDDataSourcePrmBD = new IloOplDataSource("data2.dat");
var OPDDataSourceDataBD = new IloOplDataSource("data3.dat");

//Add data source
OPDModel1.addDataSource(OPDDataSourcePrm);
OPDModel1.addDataSource(OPDDataSourcePrmBD);
OPDModel1.addDataSource(OPDDataSourceDataBD);

//PROBLEM HERE.
//Copie data elements (that in effect generate data element and copie
after)
OPDData=OPDModel1.dataElements;

//Add publisher (that will never be really part of OPDModel1)
var OPDPublisher = new IloOplDataSource("DB_Publisher.dat");
OPDModel1.addDataSource(OPDPublisher);

//Solve and postprocess
OPDModel1.generate();
if (OPDCplex1.solve())
OPDModel1.postProcess();

}

This was not so obvious to detect because some code where between all
those lines. The solution to this problem where to move the copy of the
data element after the publisher is add to the model.
It would help if there were a warning that tell us that the data source
where never populate in the model.