Others may know different, but in my five years using Anaplan I've never touched the categories and suspect they dont do anything. Maybe it is a leftover/redundant concept from days of old.
But, your post does prompt me to raise something to the community which might be worth development thinking about. Many models I see now involve 20+ functional areas...I really think that a higher level grouping of functional areas is needed for managing model content (i.e. being able to group and expand/collapse the left hand slide bar content).
