Although I think this is not the appropriate place to ask user questions (that's where fora are for), I assume you refer to J! 3.0: parent option is on the Options tab of the categories.

Sorry, I was assuming it was a bug but just my eyes! I have found it at the bottom of the details tab. I think the issue was that when I was using the code mirror editor the page appears to be blank as there is no visual box for the description. Although the options are still there upon scrolling!

No problem, James! Thanks for the follow-up.

I'm closing this item, since it's a non-issue.