Issues with Subcategories

[robtomcow]

Currently on the most recent AutoBuild version: [v20200901.1]

I'm looking to generate new Categories/Subcategories in the same vein as the Feats within "Standalone Features" but when I select "New Sub Category", enter a name, and press OK, nothing happens.

Specifically I would like to make Maneuvers, like those associated with the Battle Master subclass of Fighter, into their own "Abilities" category and Subcategory "Maneuvers" as a Feature Collection selection group.