This is not how it works in WPF. Please see:
http://msdn.microsoft.com/en-us/library/ms753391%28v=vs.110%29.aspx[
^].
You can traverse both trees on different events, but it is by far no so easy to do in WPF. I have done both things for really, really advanced and universal behavior. For an application, I would not recommend to bother. You can simply give the required particular UI element in XAML and access it by name. If you have some special concern about it, please clearly explain your idea on why doing so, what is your ultimate goal. Then would be able to think of something else.
—SA