Index: src/wp-admin/css/list-tables.css
===================================================================
--- src/wp-admin/css/list-tables.css	(revision 58576)
+++ src/wp-admin/css/list-tables.css	(working copy)
@@ -1131,7 +1131,7 @@
 	width: 75%;
 }
 
-.inline-edit-row #post_parent,
+.inline-edit-row select[name="post_parent"],
 .inline-edit-row select[name="page_template"] {
 	max-width: 80%;
 }
Index: src/wp-admin/includes/class-wp-posts-list-table.php
===================================================================
--- src/wp-admin/includes/class-wp-posts-list-table.php	(revision 58576)
+++ src/wp-admin/includes/class-wp-posts-list-table.php	(working copy)
@@ -1837,6 +1837,9 @@
 
 							if ( $bulk ) {
 								$dropdown_args['show_option_no_change'] = __( '— No Change —' );
+
+								// Make bulk edit "id" attribute different from the quick edit one.
+								$dropdown_args['id'] = 'bulk_edit_post_parent';
 							}
 
 							/**