Layers are misbehaving and overlaying base layer

I have a slide that has multiple layers. For some reason parts of these layers are overlapping onto the base layer preventing me from seeing what is on the base layer when I am authoring it. Note that when I preview the slide the base layer shows up perfectly. I think this might be a gliche in Storyline. Can someone please advise. Thank you.

One other thing, is there a limit to the number of layers that you can have on a slide. I am wondering in that is what is causing the problem. Note that I have 19 layers on the slide.