We can build the same project with Test Studio 2013.2.1210. 

After we upgraded Test Studio to 2013.2.1327, we can no longer build the project. We receive more than 70 errors like:
'Project.Pages.Page.SilverlightApp0Element' does not contain a definition for 'LoginPasswordBoxPasswordbox' and no extension method 'LoginPasswordBoxPasswordbox' accepting a first argument of type 'Project.Pages.Page.SilverlightApp0Element' could be found (are you missing a using directive or an assembly reference?)	

After further examination, we can see that these elements are present in Elements Explorer. 

This issue can also be reproduced with Test Studio 2013.2.1501

Steps to reproduce and the test project are attached in the internal description.