Current behaviour:

Since the 1.5 update, whenever ItemsSource is changed, SelectedItem is set to the first item in ItemsSource. This overwrites any selection that the user might have previously made.

Expected behaviour:

If SelectedItem exists in the new ItemsSource, it shouldn't change. If it doesn't, the selection should be cleared.

Steps to reproduce:

See the demo in this branch. Specifically, this commit.