I have been taken by surprise when a newly added vocabulary showed up in the "Product Catalog" menu ares for two Product Displays where the vocabulary applies. I created other vocabularies, but these haven't shown up in the same area. I compared the two vocabularies side-by-side, but don't see the difference between the two. Any thoughts?

1. Created new vocabulary under Structure > Taxonomy > Add Vocabulary
2. Added term reference field to "Product Display" referencing new vocabulary
3. Created new product and found this field in the "Product Catalog" area

The other new vocabularies are referenced at the Product Variation level instead. Is that why I am seeing the difference in behavior?

I wanted to use a new vocabulary because I would like to take advantage of hierarchy. I could go back to a list, but would prefer the vocab/taxonomy route.

Help is appreciated, as always!
keb