Displaying the category hierarchy on the writing page and in quickedit field in wp-admin

[hetjens]

The list of the categories on the writing page and in the quickedit field ignores the hierarchy of the categories and displays all categories on the same level.

[hakre]

Can confirm that, it partly ignores that. I was not able to get deeper into the issue, but the listing is "under heavy fixing" anyway and I smell a lot of probs in the code there.

[Denis-de-Bernardy]

probably a dup of #8613