I am having the exact same issue as the user above. The DateTimePicker was working perfectly fine and then just started to throw the following exception while being rendered:
Cannot find resource named 'InvertedBooleanToVisibilityConverter'. Resource
names are case sensitive.
The only thing that changed in my dev environment is that I installed the ASP.NET and Web Tools 2012.2 Update. The stack trace of the exception is as follows: