Hello,

It has been a while since you have made your post, in case you still need support I will be glad to assist you further. I suppose the other community members can benefit from this answer as well. I have been looking into your post and I suggest you use the GetFocusedElement static method of the FocusManager class. Here you can read more about this method:

http://msdn.microsoft.com/en-us/library/ms604088.aspx

Feel free to write me if you have further questions.