How to locate where a Master slide layout is used in a course.

I have SAME issue with Articulate Storyline. One Master says it's used by 2 slides. I have right-clicked to confirm EVERY slide in my project. I also put a BIG RED BOX on top of the slide. Thinking that "This will surely stand out!" Right? Wrong..... I even looked in all of my LAYERS. Nothing. I cannot find the rogue Master. I have saved as.... and moved on. Would be nice to at least see a LIST of slides that use that particular Master. What d'ya think Articulate? I saw another request for this 3 years ago!