TinyMCE: fix error and PHP warning when adding more than one instance in RTL mode.

Part props maimairel. Fixes #31578.
Built from https://develop.svn.wordpress.org/trunk@31874


git-svn-id: http://core.svn.wordpress.org/trunk@31853 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -2906,9 +2906,15 @@ function _config_wp_siteurl( $url = '' ) {
 function _mce_set_direction( $input ) {
 	if ( is_rtl() ) {
 		$input['directionality'] = 'rtl';
+
+		if ( ! empty( $input['plugins'] ) && strpos( $input['plugins'], 'directionality' ) === false ) {
 			$input['plugins'] .= ',directionality';
+		}
+
+		if ( ! empty( $input['toolbar1'] ) && ! preg_match( '/\bltr\b/', $input['toolbar1'] ) ) {
 			$input['toolbar1'] .= ',ltr';
 		}
+	}
 
 	return $input;
 }

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta2-31873';
+$wp_version = '4.2-beta2-31874';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.