title: Remove first element from SortedSet c#
body: <p>I have a <code>SortedSet</code> of custom objects and I want to remove the first element, which I take it with <code>First()</code> function from the <code>SortedSet</code> collection. The problem is that doesn't work and I don't know why.</p>
  
  <p>Any help?</p>
  
  <p>[edit] My code</p>
  
  <p>URL u = Queue.First();
  Queue.Remove(u);</p>
  
  <p>where URL is a custom class</p>