Can't export anything from my Package.

I can't seem to make my package export anything at all(for Visual Studio), using MEF. 


For example, code:

    [Export(typeof(IClassifierProvider))]
    [ContentType("Code")]
    public class ClassificationSambanProvider : IClassifierProvider
    {

      IClassifierProvider.GetClassifier(ITextBuffer textBuffer)
        {

            return null;
        }
    }

I have done some serious debugging, and I've found out that:

1) GetClassifier is never called, despite what ContentType might be(Any/Text/Code/etc)
2) In fact, ClassificationSambanProvider is never initialized at all, how do I know this? In deep visual studio implementation, there's a part where all the providers are imported, as such:

[ImportMany]
public List<IClassifierProvider> Providers { get; set; }

The thing is, my provider is not there. Using VS2013! Never had this problem in VS2012. Is there any secret attribute I should apply? Why is my Provider never initiated?

It seems to me that there's problem with MEF, and importing. It does not seem to import stuff from my package?!

When I do the MEF test myself, it works:

            var catalog = new AssemblyCatalog
             (System.Reflection.Assembly.GetExecutingAssembly());
		    try
		    {
		        var container = new CompositionContainer(catalog);
		        container.ComposeParts(this); // after this, Providers includes my provider.
		    }
		    catch (Exception e)
		    {
		    }

It seems that the Visual Studio never calls the AssemblyCatalog() on my Package. 

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C#/C++ | WPF/DirectShow/OpenGL/Winapi/