Remember how you started out with a couple of slide collections with just a few slides in each?

Your content has gradually grown, and you now have content that more represents the real world: multiple slides and stains are grouped by patient and represent real-world cases.

Showing all of your slides as a single list becomes messy, and so you're rather see the slides grouped properly.

You can do this by creating a new level of hierarchy in your folder structure. For any case that goes under lung, you create a new folder, and move the corresponding slides over to their new location.