Jasper Denkers

We used the beta you linked, and now it worked without problems. Thanks.

Found a solution. It is a WordPress builtin functionality, not a bug. Could be prevented with the ‘wp_terms_checklist_args’ filter.

Below an example for use with Custom Post Type ‘product’ and Custom Taxonomy ‘product_category’:

add_filter( 'wp_terms_checklist_args', 'checked_not_ontop', 1, 2 );

function checked_not_ontop( $args, $post_id ) {
    if ( 'product' == get_post_type( $post_id ) && $args['taxonomy'] == 'product_category' )
        $args['checked_ontop'] = false;

    return $args;
}

http://core.trac.wordpress.org/ticket/10982
http://core.trac.wordpress.org/ticket/20054

Noticed something different. It seems like the problem is only there when a top level category (with 2 or more levels of childs) is selected, and the childs aren’t. The selected top level categorie is moved to the top of the list (as is happing to all selected categories), but the unselected childs stay on the same spot in the list and therefore aren’t shown as child, but as top level category.