procedure TForm1.FormCreate(Sender: TObject);
begin
  EDBTable1.open;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  //CustomerID is primary key. CustomerNo is a secondary index.

   //This causes the problem if IndexName is blank (using primary key).
  EDBTable1.Locate('CustomerNo', 1002, []);
   //This causes the problem if IndexName is CustomerNo (secondary index).
  //EDBTable1.Locate('CustomerID', 10002, []);
end;