Categories lose hierarchy order once assigned to post

Question

I setup some hierarchical categories and when I assign them to a post the widget reflows and loses the hierarchy display. Example:

- Education Services
-- Arts & Archives
--- Fine Arts
-- Reference
-- Health Sciences

When selecting "Education Services" & "Reference" (marked with 'x') the widget appears like this:

x Education Services
-x Reference
- Arts & Archives
-- Fine Arts
- Health Sciences

So since the selected (top-level) parent goes to the top, all children besides the selected one look they have lost their parent (even though they actually have not).

I have read some other forums post/support tickets but not much about this issue. Any suggestions?

Answer 1

You could try out Scribu's plugin, i believe this addresses the very problem you're describing which has been reported on Trac a handful of times(but closed/deleted).

Category Checklist Tree by scribu
http://wordpress.org/extend/plugins/category-checklist-tree/

Related tickets:

• http://core.trac.wordpress.org/ticket/14723
• http://core.trac.wordpress.org/ticket/10982

Hope that helps.. :)

Answer 2

Based on the plugins Category Checklist Tree and Categories in Hierarchical Order, you could directly use this filter in your function.php file without adding any plugin:

add_filter('wp_terms_checklist_args', function($args, $idPost) {
    $args['checked_ontop'] = false;

    return $args;
}, 10, 2);

It is also possible to apply this filter only to a specific taxonomies:

add_filter('wp_terms_checklist_args', function($args, $idPost) {
    $taxonomies = ['foo', 'bar'];

    if (isset($args['taxonomy']) && in_array($args['taxonomy'], $taxonomies)) {
        $args['checked_ontop'] = false;
    }

    return $args;
}, 10, 2);

Answer 3

I developed a plugin that solves this problem. Besides preserving the hierarchy of categories, this plugin adds a toggle style the category tree.

See the official plugin page: http://www.rafaelmarques.com/wordpress/plugins/wp-best-tree/