Cannot open multiple files when implementing IVSTextViewCreationListener.

Question

In the Visual Studio 2010 SDK, I am able to implement the IVsTextViewCreationListener.VsTextViewCreation method:

    Public Sub VsTextViewCreated(ByVal textViewAdapter As Microsoft.VisualStudio.TextManager.Interop.IVsTextView) Implements Microsoft.VisualStudio.Editor.IVsTextViewCreationListener.VsTextViewCreated
       Dim textView As ITextView = AdapterService.GetWpfTextView(textViewAdapter)
       If textView Is Nothing Then
           Return
       End If

       Dim createCommandHandler As Func(Of TestCommandHandler) = Function() New TestCommandHandler(textViewAdapter, textView)
       textView.Properties.GetOrCreateSingletonProperty(createCommandHandler)
   End Sub

I am also Importing IvsEditorAdaptersFactoryService.

Now, how do I open up multiple files each in their own tab? Once the first file is open, each time I click the "Open" icon nothing happens.

Thanks, Nick