Index: src/wp-includes/css/editor.css
===================================================================
--- src/wp-includes/css/editor.css	(revision 30365)
+++ src/wp-includes/css/editor.css	(working copy)
@@ -2178,6 +2178,7 @@
 	transition-timing-function: ease-in-out;
 }
 
+/* @noflip */
 .focus-on #adminmenuback,
 .focus-on #adminmenuwrap {
 	-webkit-transform: translateX( -100% );
@@ -2185,6 +2186,14 @@
 	transform: translateX( -100% );
 }
 
+/* @noflip */
+.rtl.focus-on #adminmenuback,
+.rtl.focus-on #adminmenuwrap {
+	-webkit-transform: translateX( 100% );
+	-ms-transform: translateX( 100% );
+	transform: translateX( 100% );
+}
+
 .focus-on .screen-meta-toggle {
 	-webkit-transform: translateY( -100% );
 	-ms-transform: translateY( -100% );