Using the IsExpanded property is the way to go. If it do not work in your case, please send us a sample project so we can investigate.
TRY TELERIK'S NEWEST PRODUCT - EQATEC APPLICATION ANALYTICS for WINDOWS PHONE 7.
Learn what features your users use (or don't use) in your application. Know your audience. Target it better. Develop wisely.
Sign up for Free application insights >>