Winforms BindingSource .AddNew() works but .CancelNew() does nothing

Question

Per screen capture below:

1. bindingSource1.AddNew() works as expected. A new item appears and becomes current.

2. bindingSource1.CancelNew() does nothing. Per debug messages my button handler is clearly being called, and it correctly attempts to cancel list index 3, but the new user is not actually removed.

The same problem occurs regardless of whether bindingSource1 is backed by BindingList<User> or List<User> (shown).