title: I want an hourglass while my IsAsync binding is busy; possible?
body: <p>I've currently got XAML code like this:</p>
  
  <pre><code>&lt;ListView Name="fileLV" SelectionMode="Extended" ItemsSource="{Binding path=DataContext.SelectedAsset.Files,ElementName=selectionView,IsAsync=True}"/&gt;
  </code></pre>
  
  <p>That "Files" property takes fifteen seconds to return. The whole time the user is wondering what's going on. I've seen some other code to show the fallback value or use multiple bindings, but those don't rely imply "leave this control alone" like an hourglass over that control would imply.</p>
  
  <p>What I want is to be able name a binding and then bind some other properties to that binding's IsBusy property. I want a trigger to change the cursor on that listview while his binding is busy. Is there any existing WPF framework help for this?</p>