anchor.diff:    printPointer('dlg', dlg);
     printPointer('dlg->lpVtbl', dlg.ref.lpVtbl);
   
  -  // This gives the correct value.
     printPointer(
         'dlg->lpVtbl->QueryInterface', dlg.ref.lpVtbl.ref.QueryInterface);
     printPointer('dlg->lpVtbl->AddRef', dlg.ref.lpVtbl.ref.AddRef);
  
positive.code: import 'package:win32/win32.dart';
  
  class IFileDialogVtbl extends Struct {
    Pointer<NativeFunction> QueryInterface;
    Pointer<NativeFunction> AddRef;
    Pointer<NativeFunction> Release;
    Pointer<NativeFunction> Show;
    Pointer<NativeFunction> SetFileTypes;
    Pointer<NativeFunction> SetFileTypeIndex;
    Pointer<NativeFunction> GetFileTypeIndex;
    Pointer<NativeFunction> Advise;
    Pointer<NativeFunction> Unadvise;
    Pointer<NativeFunction> SetOptions;
    Pointer<NativeFunction> GetOptions;
    Pointer<NativeFunction> SetDefaultFolder;
    Pointer<NativeFunction> SetFolder;
    Pointer<NativeFunction> GetFolder;
    Pointer<NativeFunction> GetCurrentSelection;
    Pointer<NativeFunction> SetFileName;
    Pointer<NativeFunction> GetFileName;
    Pointer<NativeFunction> SetTitle;
    Pointer<NativeFunction> SetOkButtonLabel;
    Pointer<NativeFunction> SetFileNameLabel;
    Pointer<NativeFunction> GetResult;
    Pointer<NativeFunction> AddPlace;
    Pointer<NativeFunction> SetDefaultExtension;
    Pointer<NativeFunction> Close;
    Pointer<NativeFunction> SetClientGuid;
    Pointer<NativeFunction> ClearClientData;
    Pointer<NativeFunction> SetFilter;
  }
  
  class IFileDialog extends Struct {
  
negative.code:   printPointer('dlg->lpVtbl->Show', dlg.ref.lpVtbl.ref.Show);
    printPointer('dlg->lpVtbl->SetFileTypes', dlg.ref.lpVtbl.ref.SetFileTypes);
    printPointer('dlg->lpVtbl->SetTitle', dlg.ref.lpVtbl.ref.SetTitle);
  
    print('---');
    printPointer('dlg->lpVtbl->QueryInterface', dlg.ref.lpVtbl.elementAt(0));
    printPointer('dlg->lpVtbl->AddRef', dlg.ref.lpVtbl.elementAt(1));
    printPointer('dlg->lpVtbl->Release', dlg.ref.lpVtbl.elementAt(2));
    printPointer('dlg->lpVtbl->Show', dlg.ref.lpVtbl.elementAt(3));
    printPointer('dlg->lpVtbl->SetFileTypes', dlg.ref.lpVtbl.elementAt(4));
    printPointer('dlg->lpVtbl->SetTitle', dlg.ref.lpVtbl.ref.SetTitle);
  }
  