title: Entity Framework returns null for Include properties
body: <p>I got 3 entities(tables) that have many to many connections:</p>
  
  <pre><code>public class AccUserRole
  {
      public long Id { get; set; }
      public string RoleName { get; set; }
      public List&lt;AccAdGroup&gt; Groups { get; set; }
      public List&lt;AccScreen&gt; Screens { get; set; }
  }
  
  public class AccAdGroup
  {
      public long Id { get; set; }
      public string AdIdent { get; set; }
      public List&lt;AccUserRole&gt; Roles { get; set; }
  }
  
  
  
  public class AccScreen
  {
      public long Id { get; set; }
      public string ScreenIdent { get; set; }
      public List&lt;AccUserRole&gt; Roles { get; set; }
  }
  </code></pre>
  
  <p>I wanted to get all Roles(including their screens and groups) that has at least one of specified list of groups(the groups of the current user). So I used this query:</p>
  
  <pre><code>List&lt;AccUserRole&gt; userRoles = (from ur in db.AccUserRoles.Include("Groups").Include("Screens")
                                 from g in ur.Groups
                                 where user.Groups.Contains(g.AdIdent)
                                 select ur).ToList();
  </code></pre>
  
  <p>It gets the right roles, but the <code>Groups</code> and <code>Screens</code> properties are null. Looks like EF has a problem with using <code>Include</code> and second <code>from</code>.
  Any help on how to include the properties or rewrite the query will be appreciated.</p>