QFileDialog: (Windows) Native getSaveFileNames extension issue

When using the native filedialog on Windows for saving a file, e.g:

QString fileName = QFileDialog::getSaveFileName(0, QObject::tr("Save File"),
"/home/jana/untitled.png",
".png;;.xpm;;.jpg;;.txt;;*");

then the default windows dialog does not update the file extension when the user selects a file type that is different from the one in the file name field. This works for the native dialogs in non-Qt applications. Since the native dialog is being used this is probably not something we can change in our code, but maybe we could use a different native filedialog where this works ?