This is in beta mode and under test so naming this test page with ‘zzz’ puts it at the end of the list out of the way.
The following screenshots are for debugging. There are bugs! The displayed thumbnails from a ‘successful’ search all just link to the gallery they’re on. Clicking on one may open the gallery as a ‘post’ – narrower, and instead of the actual page I created that has the gallery shortcode.
The Robosoft galleries can have their own search box (red rectangle to the right of a menu). I added it to larger galleries. It works by restricting the gallery to found matches. It’s usually necessary to click on Load More to see successful searches.