If you want to search for all instances of a particular kind of highlighting in a resource (or your whole library), the logical thing to do would be to search for * (wildcard character) with that highlighting style checked in the "All Text" dropdown. It sort of works. At least it finds all books that have any of that kind of highlighting in them. But it only shows the first hit within each article, with only the first 8 words (max) of highlighting highlighted in the search results. If the article has more than one chunk of highlighting, the remaining ones do not show up in the search results. And the hit counts are very huge and unrelated to the actual number of chunks of highlighted text (which is what we'd want it to count). It seems to be counting all the words that are highlighted in each article. It also counts the words inside the footnotes if your highlighting happens to span across some footnote reference marks.
It's also exceedingly slow and unusable right now. It takes close to an hour to search my whole library. And a long number of minutes to search one resource.
If this isn't the way the search for highlighting feature was designed to work (which I suspect it wasn't) please fix it so it works this way. I know you can search for what books have that highlighting style in them and then do Find Next highlight to go through them all. But if you've got a big book with lots of highlighting in it, that's pretty cumbersome. Search should be able to search for them all at once so you can skim through them and find ones you want to revisit in context.
UPDATE: Here's a screen shot:

Here's a screenshot of the location where that second hit is found in the text. Notice that the next highlight down ("pre-critical approach") does not appear in the search results.

Also, the fact that search is word-based means that the highlighting is weird. You see bits of the yellow highlighted whitespace and punctuation showing through the words that are highlighted because they matched the wildcard character.
I guess what I'm suggesting is that a simple wildcard search for highlighting be treated as a special case, and match entire chunks of highlighting, rather than every word within that highlighted text individually. That should fix all of the above problems.