Make parent category not selectable when it has child categories

Question

I'm trying to find a way of disabling the selection of the parent category within Wordpress 3.5.1 (post editor screen) only when that parent category contains child categories.

My structure:

• Category 1 (no children, allow users to post, keep selection option)
• Galleries (parent category WITH children, remove selection option to stop users posting)
  • User 1 (child category, allow user to post, keep selection option)

A jQuery solution to disabling the section of all parent categories (regardless of having child categories or not) can be found here:

Make parent categories not selectable

Answer 1

I disabled the parent boxes to avoid shifting parents to the left.

add_action( 'admin_footer-post.php',     'wpse_98274_disable_top_categories_checkboxes' );
add_action( 'admin_footer-post-new.php', 'wpse_98274_disable_top_categories_checkboxes' );

/**
 * Disable parent checkboxes in Post Editor.
 */
function wpse_98274_disable_top_categories_checkboxes() {
    global $post_type;

    if ( 'post' != $post_type )
        return;
    ?>
        <script type="text/javascript">
            jQuery( "#category-all ul.children" ).each( function() {
                jQuery(this).closest( "ul" ).parent().children().children( "input" ).attr( 'disabled', 'disabled' )
            });
        </script>
    <?php
}

However, once the categories are pulled out of order for that horrid "feature" that moves them to the top of the box, the jQuery fails. I borrowed this code from a plugin.

add_filter( 'wp_terms_checklist_args', 'wpse_98274_checklist_args' );

/**
 * Remove horrid feature that places checked categories on top.
 */
function wpse_98274_checklist_args( $args ) {

    $args['checked_ontop'] = false;
    return $args;
}

Answer 2

You can use this plugin, it will solve your issue

https://wordpress.org/plugins/adjust-admin-categories/

Answer 3

If you're looking to use this with Custom Posts, replace where it says post in the if statement with the slug of your post type.

With Custom Taxonomies, replace where it says #category-all with the name of your taxonomy (e.g., #taxonomyname-all).

Your situation will most likely be both if you are looking at this.

For multiple taxonomies/post types at the same time: One simple option is to duplicate the entire code, and in addition to the changes above, make any new name where it says wpse_98274_disable_top_categories_checkboxes - the 98274 is just referencing this page (look at this pages URL) and not calling anything special in WordPress. Or more elegant is to make multiple if statements.