Move category to a sub-category

[hammer_ortiz]

I am trying to move a category from having no parent category to be under a different primary category. But the option is not appearing in the category edition window (as can be seen in the attached screenshot)

Is there any way to move the category, all its subcategories and posts keeping the category structure?

[pfaffman (Jay Pfaffman)]

There are (currently?) only two levels of categories supported. Search for “time we talk about tags”.