title: Many to many relationship detecting changes
body: <p>I am trying to understand why DbContext doesn't detect changesin many-to-many relationship. This is what I have set in model configuration:</p>
  
  <pre><code>this.Configuration.ValidateOnSaveEnabled = false;
  this.Configuration.ProxyCreationEnabled = false;
  this.Configuration.LazyLoadingEnabled = false;
  </code></pre>
  
  <p>This is the test code:</p>
  
  <pre><code>var book = Context.Set&lt;Book&gt;().Where(b =&gt; b.Id == 1).Single();
  var author = Context.Set&lt;Author&gt;().Where(a =&gt; a.Id == 2).Single();
  
  book.Authors.Add(author);
  </code></pre>
  
  <p>if I check for changes, it doesn't report any:</p>
  
  <pre><code>// returns false
  _context.ChangeTracker.Entries().Any(e =&gt; e.State == EntityState.Added || e.State == EntityState.Modified || e.State == EntityState.Deleted);
  </code></pre>
  
  <p>If I save changes, changes are updated to database correctly.</p>
  
  <pre><code>// 1 record added to BookAuthors table
  _context.SaveChanges();
  </code></pre>
  
  <p>Why is DbContext not tracking changes for many-to-many? WCF is not involved, this is a direct connection to Sql server.</p>