Listbox: Setting IsSynchronizedWithCurrentItem to true is one way
When setting IsSynchronizedWithCurrentItem to true, the RadListBox behaves differently from the standard ListBox; changing the selection in the RadListBox does not update the current item of the underlying ICollectionView.
Thank you for your report!
Actually, this is a known issue to us. There are some scenarios in which RadListBox is not consistent with the MS ListBox when an ICollectionView is used as a source and the IsSynchronizedWithCurrentItem property is set to True. They are already logged in our system and I will relate your report to them, so it is taken into consideration when implementing the needed modifications of the control.
All the best,