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
v8::Local<v8::Value> val,
                     file_dialog::DialogSettings* out) {
    mate::Dictionary dict;
    if (!ConvertFromV8(isolate, val, &dict))
      return false;
    dict.Get("window", &(out->parent_window));
    dict.Get("title", &(out->title));
    dict.Get("buttonLabel", &(out->button_label));
    dict.Get("defaultPath", &(out->default_path));
    dict.Get("filters", &(out->filters));
    dict.Get("properties", &(out->properties));
    return true;
  }
};
}  
namespace {
void ShowMessageBox(int type,