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::Filter* out) {
    mate::Dictionary dict;
    if (!ConvertFromV8(isolate, val, &dict))
      return false;
    if (!dict.Get("name", &(out->first)))
      return false;
    if (!dict.Get("extensions", &(out->second)))
      return false;
    return true;
  }
};
template<>
struct Converter<file_dialog::DialogSettings> {
  static bool FromV8(v8::Isolate* isolate,