For many months I've experiance the same issue has laid out here...
I thought it would be fixed.
I created 9 categoryes 3 parents, 3 child and a further 3 child of the first 3 children.
Only 3 categories are displayed on the categories admin page. Even when adding posts to the hidden categories they do not show. They do show if I delete the 3 parents, not only do the other show but they are indented correctly.
Is WordPress treating the true parent differently from a parent of a 3rd level of categories ?
I really want this fixed and so do a couple of hundred of my plugin users.
Thanks for any attention.