Message when no posts returned?

Hello,

I am using your plugin on a client’s site, and it has been a massive help. One thing I’m running into, though, is that in instances where the shortcode returns no results, I’d like it to display some sort of “No posts found” message, but it just displays nothing. Am I missing something, or is there something I need to do or an add-on I need to get to display a “no posts” message if there are no results?