Make sure you have WBC included in your top commentaries.
Open a passage guide and do a search on any verse in Ecclesiastes.
Click on the WBC link in the Commentaries section of the PG.
It jumps to the translation of that verse in the commentary -- not useful. I want to go to the place where the commentary discusses this verse, which I now have to manually scroll down several pages to find.
Ecclesiastes is the only volume of WBC I've discovered (doing some random spot checking) that has this problem, though I haven't done an exhaustive check. It happens for every verse I've tried in Ecclesiastes (again, just some spot checking).
Update: Just for explicity clarification, in all the other volumes of WBC besides Ecclesiastes (the only one I've discovered that has this problem), when you click on the link in the PG, it does go to the commentary on that verse, not the translation. That's what I'd expect for Ecclesiastes, too.