The product groups page was orphaned. Not linked in the sidebar, not reachable through navigation, not mentioned in any tooltip or help text. A full page at /product-groups that managed the containers products live in — but you had to know the URL to find it.
The products page, meanwhile, showed a flat list of products without any sense of which group they belonged to. Two pages that needed each other, separated by a URL nobody typed.
The unified Product Manager collapsed them into one. Groups render as expandable accordion panels with products nested inline as compact rows. Each group panel shows its title, category type badge, product count, and edit/delete actions. Products within show visibility, pricing method, price summary, discount status. The "Add Product" button inside each group pre-selects the group context — you're already looking at the right container when you create the product.
No backend changes. The API was already well-structured. The problem was entirely presentational — two good data endpoints feeding two separate pages when one page with hierarchy would have been right from the start.