NSSavePanel (and NSOpenPanel, as a subclass) supports a `message` (via `setMessage:message` in Obj-C), which allows a message to be displayed even when the panel is attached to a parent. Right now, `title` is useless for attached dialogs.

atom/browser/api/atom_api_dialog.cc
const std::vector<std::string>& buttons,
                    int default_id,
                    int cancel_id,
                    int options,
                    const std::string& title,
                    const std::string& message,
                    const std::string& detail,
                    const std::string& checkbox_label,
                    bool checkbox_checked,
                    const gfx::ImageSkia& icon,
                    atom::NativeWindow* window,
                    mate::Arguments* args) {
  v8::Local<v8::Value> peek = args->PeekNext();
  atom::MessageBoxCallback callback;
  if (mate::Converter<atom::MessageBoxCallback>::FromV8(args->isolate(),
                                                        peek,
                                                        &callback)) {
    atom::ShowMessageBox(window, (atom::MessageBoxType)type, buttons,
                         default_id, cancel_id, options, title, message, detail,
                         checkbox_label, checkbox_checked, icon, callback);
  } else {
    int chosen = atom::ShowMessageBox(window, (atom::MessageBoxType)type,
                                      buttons, default_id, cancel_id,
                                      options, title, message, detail, icon);
    args->Return(chosen);
  }
}
void ShowOpenDialog(const file_dialog::DialogSettings& settings,