In my application, I load TreeGridView nodes on demand using async web service calls . 99% of the time, the service call is successful, but sometimes it fails due to various authorization issues. When this happens, the Expander disappears. I need it to remain visible so the user can retry the expansion after correcting the authorization issue. I've tried adding a call to TreeListBoxItemAdapter.InvalidateChildren(), as per the documentation, but this immediately calls TreeListBoxItemAdapter.GetChildren() which returns an empty ObservableCollection (because there are no children yet). How do I get the Expander to remain visible in this use case?