title: Missing PropertyChanged event when BindingList elements has properties changed
body: <p>I have a class <code>ViewModel</code> that has a property <code>MyList</code> of type <code>BindingList&lt;Foo&gt;</code>.</p>
  
  <p><code>ViewModel</code> implements <code>INotifyPropertyChanged</code>.</p>
  
  <p>Foo has the property <code>FooProp</code>.</p>
  
  <p><code>Foo</code> implements <code>INotifyPropertyChanged</code></p>
  
  <p>ViewModel has this property:</p>
  
  <pre><code>public bool IsButtonEnabled
    {
      get
      {
        return MyList.Any(x=&gt; x.FooProp!=null);
     }
  }
  </code></pre>
  
  <p>I have a view with a button. The Enabled property of the button is bound to <code>IsButtonEnabled</code>.</p>
  
  <p>But the button doesn't get enabled when an element of <code>MyList</code> has it's <code>FooProp</code> set. I've noticed that <code>ViewModel</code> doesn't fire a <code>PropertyChanged</code> event here. Why not? And how should I go about for the view model to notice that it's <code>IsButtonEnabled</code> property actually has changed?</p>