In Expression Blend and WPF i've created a datasource at the application level ( in App.xaml called ViewModelDataSource ). So, doing my bindings is a snap, however if I create a user control and in that user control set any data contexts to the ViewModelDataSource I created in App.xaml the parent control that contains that user control no longer renders in blend. Instead I get that nasty red exclamation mark and the error output is: Cannot find resource named '{ViewModelDataSource}'... The error position that it is reporting is at the data context declaration in the user control. It does however run fine ( i.e. the static resource resolution runs great )