data binding - Expression Blend does not list my application's objects in CLR objects -

I follow the video tutorial of binding data with Visual Studio / Expression Blend. In the tutorial, the application's custom object Are listed when the presenter clicks on the "+ CLR Object" button, but when I do this, the objects of my application are not listed.

What do I need to do to get my application items listed here?

Do you have a reference between projects? It appears that there is no reference to parents in the child's project, so they can be raised.