Entity State Change before entity add to manager

   Hello Everyone 

I am seeing something with my entity manager when adding a new entity that doesn't make sense to me.
From all my reading it seems that when I call 

X foo = EntityManger.CreateEntity<X>(); 

I will get a new instance of the entity of type X and its entity state will be detatched until I explicity call EntityManager.AddEntity(foo).

This is exactly how it works if my type X does not have property of another type on it.  The propblem seems to happen when I have a type X that has a property of type Y in it.  Then when I set the Type Y property the entity state then changes to added and if I look at the EntityManager.Xs I see the entity already attached there. 

To try and illustrate this better here is my code:

TypeX foo= EntMan.CreateEntity<TypeX >();

//at this point foo has an entitystate = detatched and EntMan.TypeXs does not contain anything
foo.FooID = Guid.NewGuid();
foo.SomeProp1 = "Something";

//bar is a type that is already in cache and has an entity state = unchanged
foo.SomePropThatIsOfOtherTypeInCache = bar;
//after setting SomePropThatIsOfOtherTypeInCache we can see that 
//foo.entitystate = added and EntMan.TypeXs now conatins the foo entity.

At this point because the entitystate is added and the entitymanager already contains the entity there is no reason to call EntityManager.AddEntity(foo).

I cannot find any documentation that mentions this functionality.  Is this by design or do I not understand how this is suppose to work.

Thanks
Blaine