Quando aggiungi un ulteriore livello di nidificazione, tutte le categorie, comprese le sottocategorie, vengono visualizzate nella pagina delle categorie

[pfaffman (Jay Pfaffman)]

It’s generally considered a bad idea to have more than a couple hundred categories. Maybe have a look at It’s Time We Talked About Tags. The sub sub category feature is largely unsupported last I knew, but perhaps there’s a way to hide them as you wish.