Thanks, but I don't know what you mean by "operating one or two paragraphs at a time". I guess pinning search terms means showing them at the top so that you can click on them to search them? I don't think that would much value, because it would be faster to type, except on mobile. It might be useful as a reminder, though.

EDIT: Do you mean having two search fields at the same time? I always just open two windows when I need that, but it would probably make sense for thinktype to support it "natively".