Index: src/wp-admin/includes/meta-boxes.php
===================================================================
--- src/wp-admin/includes/meta-boxes.php (revision 33321)
+++ src/wp-admin/includes/meta-boxes.php (working copy)
@@ -509,7 +509,38 @@
- $tax_name, 'hide_empty' => 0, 'name' => 'new' . $tax_name . '_parent', 'orderby' => 'name', 'hierarchical' => 1, 'show_option_none' => '— ' . $taxonomy->labels->parent_item . ' —' ) ); ?>
+ $tax_name,
+ 'hide_empty' => 0,
+ 'name' => 'new' . $tax_name . '_parent',
+ 'orderby' => 'name',
+ 'hierarchical' => 1,
+ 'show_option_none' => '— ' . $taxonomy->labels->parent_item . ' —',
+ );
+ /**
+ * Filters the taxonomy parent drop-down on the Post Edit page.
+ *
+ * @since 4.4.0
+ *
+ * @param array $parent_dropdown_args {
+ * Optional. Array of arguments to generate a categories drop-down element.
+ *
+ * @type string $taxonomy Name of the category to retrieve. Default 'category'.
+ * @type bool $hide_if_empty True to skip generating markup if no categories are found.
+ * @type string $name Value for the 'name' attribute of the select element. Default 'cat'.
+ * @type string $orderby Which column to use for ordering categories. See get_terms() for a list
+ * of accepted values. Default 'id' (term_id).
+ * Default false (create select element even if no categories are found).
+ * @type bool|int $hierarchical Whether to traverse the taxonomy hierarchy. Accepts 0, 1, or their bool
+ * equivalents. Default 0.
+ * @type string $show_option_none Text to display for showing no categories. Default empty.
+ * }
+ *
+ */
+ $parent_dropdown_args = apply_filters( 'post_edit_category_parent_dropdown_args', $parent_dropdown_args );
+ wp_dropdown_categories( $parent_dropdown_args );
+ ?>