Minor comments

The plugin works as promised, except that if you haven’t published the page (you’re previewing a draft) the form submission doesn’t work. The article vanishes and you’re left looking at the previous article.

Also, the left and right result set navigator buttons aren’t symmetrical. The “forward” button moves you on by N pages, but the “back” button only moves you back by one. Which is a pain if you want to get back to the first page of hits …