Mientras intento desarrollar mi primer complemento VS, tengo problemas para disparar eventos DTE2.

Básicamente, los eventos DocumentOpened y LineChanged no se activan por algún motivo. ¿Qué parte importante extrañé?

namespace TestAddin {
  public class Connect : IDTExtensibility2 {
    private AddIn _addInInstance;
    private DTE2 _applicationObject;

    public void OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom) {
      _applicationObject = (DTE2) application;
      _addInInstance = (AddIn) addInInst;

      _applicationObject.Events.DocumentEvents.DocumentOpened += InitializeFoldingOnDocument;
      _applicationObject.Events.TextEditorEvents.LineChanged += UpdateFoldingOnDocument;
    }

    private void UpdateFoldingOnDocument(TextPoint startpoint, TextPoint endpoint, int hint) {
      RegionFolding(_applicationObject.ActiveDocument);
    }

    private void InitializeFoldingOnDocument(Document document) {
      RegionFolding(document);
    }

    private void RegionFolding(Document _document) {
      // Do the folding [...]
    }

    // Other IDTExtensibility2 Members [...]
  }
}