It looks like an old version of the highlight question made it up to the website. Not sure how or when that happened, but I've gone ahead and re-uploaded the latest version of the question. If you download the question again, you should have the missing button.
The "per-word" version of the question that Paul mentioned is a custom version of the question I made a few months ago. I planned on putting it up on the community library as a separate library item once any bugs got worked out, but never got around to it.