I have to entities: Company and Location (one to many). When I create new Location entity object and assign navigation property(Company) with the navigation property of already existing Location object (Location _new = new Location(); _new.Company = _old.Company). It seems that at that point newly created object is added to Object Context automatically, because when I call SaveChanges method that object is insert to database although I didn't call ObjectContext.AddObject(_new). I'm new in EF so there is probably reason why I have result like this? Is there need to assign also CompanyReference filed too and how to do it?

IDaoFactory daoFactory = new DaoFactory();
ILocationDao locaitonDao = daoFactory.GetLocationDao();
IEnumerable<Location> locations = locaitonDao.GetLocations();
Location _old = locations.First();
Location _new = new Location();
_new.LocationName = _old.LocationName;
_new.Company = _old.Company;// 1
_new.Address = _old.Address;
//...
ContactEntities.SaveChanges();//2

If I execute line (1) instantly _new object is added to object context and I can see additional datarow in my datagrid after line (2) is executed.