NullReferenceException on adding assemblies

[philipmat]

Getting a NRE in PropertyPresenter.AddAssemblyCommand_Execute:180 because _selectedConfig is null).

Exception:

System.NullReferenceException
  HResult=0x80004003
  Message=Object reference not set to an instance of an object.
  Source=<Cannot evaluate the exception source>
  StackTrace:
<Cannot evaluate the exception stack trace>

How to reproduce (current master / v1.0.0.0):

1. Start the application, click New
2. Don't change any options, go to Assemblies tab
3. Add an assembly.
4. Error manifests.

I only see _selectedConfig getting set in LoadViewFromModel and even there only if _model.ConfigName.Length > 0, otherwise it's getting set to null. However, on a new project, PropertyModel.Configs contains no config so _selectedConfig never gets set to anything.