This has happened on a couple of my WPF pages that use the GridView. I select an item on my list which populates some textboxes. I update those textboxes, click "Update" and then reload the GridView. Reloading the GridView consists of re-retrieving the data and setting the ItemsSource. On this particular page I have, it binds properly the first time, but all subsequent re-binds I get this. Any ideas what might be happening?