What is a reason that LINQ to SQL wouldn't generate a collection based on a relationship?

Question

I have a relationship between two entities (e1 and e2) and e1 has a collection of e2, however I have a similar relationship set up between (e2 and e3), yet e2 does not contain a collection of e3's, any reason why this would happen? Anything I can post to make this easier to figure out?

Edit: I just noticed that the relationship between e1 and e2 is solid and between e2 and e3 is dotted, what causes that? Is it related?

Answer 1

How do you have your FK constraints modelled?

Answer 2

the FK_Contraints are set up like this:

ALTER TABLE [dbo].[e2] WITH CHECK ADD CONSTRAINT [FK_e2_e1] FOREIGN KEY([E1Id]) REFERENCES [dbo].[e1] ([Id])

ALTER TABLE [dbo].[e3] WITH CHECK ADD CONSTRAINT [FK_e3_e2] FOREIGN KEY([E2Id]) REFERENCES [dbo].[e2] ([Id])

is this what you were asking for?