The datatemplate for the JumpList is not working anymore. This is caused by a faulty checkin.

Change Set 91919
File: JumpList.xaml

This was removed on line 40, but you will have to place it back to get the datatemplate for the jumplist working:
ContentTemplate="{TemplateBinding ContentTemplate}"

Hope this helps,
Michiel

Thanks for your feedback, I have updated the file.

Guillaume