I have tried to reproduce the reported behavior on our side and it seems that the code works as expected. Could you please share with us more information on your scenario? How do you load the items? When and how you change the selection of the control?
I have attached the project that I tested the behavior with. I tried both XAML definition and MVVM approaches. Please feel free to change the code so that the issue can be reproduced in and send it over. This will help me to better understand your scenario and requirement.
Thank you for your cooperation.
Pavel R. Pavlov
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.