title: Entity Framework Many-to-Many not loading related entities
body: <p>I have to 2 entity classes with a many-to-many relationship defined via FluentAPI. Entity1 has the virtual collection with the related Entity2-objects. Entity2 does NOT have this collection since I dont need it. 
  My classes look like this:</p>
  
  <pre><code>  internal class Franchisee : UserAccount //abstract base class with more properties
    {
          public virtual ICollection&lt;FranchiseOffice&gt; FranchiseOffices { get; set; } 
    }
  
    internal class FranchiseOffice: Office //abstract base class
    {
          &lt;many properties, but no collection for Franchisee-objects&gt;
    }
  </code></pre>
  
  <p>Configuration of the many-to-many relationship:</p>
  
  <pre><code> protected override void OnModelCreating(DbModelBuilder modelBuilder)
   {
              Database.SetInitializer(new MigrateDatabaseToLatestVersion&lt;CoreModel, Migrations.Configuration&gt;());
  
              //many-to-many relationship with only one navigation property
              modelBuilder.Entity&lt;Franchisee&gt;().HasMany(u =&gt; u.FranchiseOffices).WithMany().Map(m =&gt;
              {
                  m.MapLeftKey("FranchiseeId");
                  m.MapRightKey("FranchiseOfficeId");
                  m.ToTable("FranchiseOffices");
              });
    }
  </code></pre>
  
  <p><strong>What is working</strong>: saving the entities and linking them together via the navigation property. Data in the database looks fine; the mapping table 'FranchiseOffices' is there and filled with data.</p>
  
  <p><strong>What does not work</strong>: when I load a Franchisee, the collection 'FranchiseOffices' is NULL although data is present for it in the database.</p>
  
  <p>The only difference to online examples I can see is that I am using inherited classes on both sides. I tried querying the child-classes explicity, but the outcome was the same. Any ideas?</p>