- The single default button in the "Shutdown Computer" and "GINA failed
to load" dialogs will be automatically focused by the dialog manager,
so there is no need to invoke `SetFocus()` in their `WM_INITDIALOG`
handler -- which also erroneously returned `TRUE`, thus ignoring any
focus set by the caller :D
- Use `DeleteMenu()` instead of `RemoveMenu()` so that it'll free any
memory resources.