HML Checker

Implement a Category table view that supports infinitely deep parent/child categories, with collapse/expand buttons on each parent category. Every category will also have an "Collective Products"/"Associated Products" counters, and "Add Child"/"Delete" buttons on the left side that do their respective action.

The product counts need to be recursively calculated when the category is expanded (or made visible).
More than 1 category column can exist in a project so this will influence the counters to count products if any category columns match the one being counted.