title: ReactiveList problems
body: <p>We are relatively new to ReactiveUI so this may explain why we are having some issues with getting a view model working.</p>
  
  <p>In our view model we have a ReactiveList of a class , for which there is a 'selected' in the class.</p>
  
  <p>In the view model we want to have a 'AnySelected' property such that if there is at least 1 item in the list marked as selected then AnySelected is true.</p>
  
  <p>We are having difficulty in getting this work.</p>
  
  <p>As a small test application, with just strings, we have tried this, but messages around changes occurring don't appear.  </p>
  
  <pre><code>public class TestRx : ReactiveObject
  {
      private ReactiveList&lt;string&gt; mySelectedItems;
  
      public ReactiveList&lt;string&gt; MySelectedItems
      {
          get { return mySelectedItems; }
          set { this.RaiseAndSetIfChanged(ref mySelectedItems, value); }
      }
  
      public TestRx()
      {
          var firstList = new ReactiveList&lt;string&gt;();
  
          var t = this.WhenAnyValue(x =&gt; x.MySelectedItems);
          var t1 = t.Select(x =&gt; x ?? new ReactiveList&lt;string&gt;());
  
          var changed = t1.Select(x =&gt; x.Changed.Select(_ =&gt; Unit.Default));
          var itemChanged = t1.Select(x =&gt; x.ItemChanged.Select(_ =&gt; Unit.Default));
          var countChanged = t1.Select(x =&gt; x.CountChanged.Select(_ =&gt; Unit.Default));
  
          t.Subscribe(x =&gt; Debug.WriteLine("T HAS CHANGED {0}", x == firstList));
          t1.Subscribe(z =&gt; Debug.WriteLine("T1 Changed {0}", z == firstList));
  
          changed.Subscribe(x =&gt; Debug.WriteLine("Changed :"));
          itemChanged.Subscribe(x =&gt; Debug.WriteLine("Item Changed :"));
  
          var replacementList = new ReactiveList&lt;SelItem&gt;(new[] {
                  new SelItem() { Selected = false } 
          });
  
          Debug.WriteLine("***********************Assign 1st list");
          MySelectedItems = firstList;
          Thread.Sleep(100);
  
          Debug.WriteLine("***********************Adding item 2 list");
          MySelectedItems.Add("a new string");
          // we don't get any debug messages  as a result of the above
          Thread.Sleep(100);
  
          Debug.WriteLine("***********************Assign null");
          MySelectedItems = null;
          Thread.Sleep(100);
      }
  }
  </code></pre>
  
  <p>What are we doing wrong ?</p>