Index: src/wp-includes/class-wp-editor.php
===================================================================
--- src/wp-includes/class-wp-editor.php	(revision 33585)
+++ src/wp-includes/class-wp-editor.php	(working copy)
@@ -207,9 +207,13 @@
 			if ( $set['media_buttons'] ) {
 				self::$has_medialib = true;
 
-				if ( ! function_exists( 'media_buttons' ) )
+				if ( ! function_exists( 'media_buttons' ) ) {
+					require_once( ABSPATH . 'wp-admin/includes/admin-filters.php' );
+					if ( is_multisite() ) {
+						require_once( ABSPATH . 'wp-admin/includes/ms-admin-filters.php' );
+					}
 					include( ABSPATH . 'wp-admin/includes/media.php' );
-
+				}
 				echo '<div id="wp-' . $editor_id_attr . '-media-buttons" class="wp-media-buttons">';
 
 				/**