title: what is the difference between invalidateList and invalidateDisplayList?
body: <p>I have a DataGrid, populated with objects in an ArrayCollection.  After updating one of the objects' fields, I want the screen to update.  The data source is not bindable, because I'm constructing it at runtime (and I don't understand how to make it bindable on the fly yet -- that's another question).</p>
  
  <p>In this situation, if I call InvalidateDisplayList() on the grid nothing seems to happen.  But if I call invalidateList(), the updates happen.  (And it's very smooth too -- no flicker like I would expect from invalidating a window in WIN32.)</p>
  
  <p>So the question:  what is the difference between InvalidateList and InvalidateDisplayList?    From the documentation it seems like either one should work.</p>