Ticket #21906: 21906.patch

wp-includes/css/editor.css

@@ -1046 +1046 @@
 }
 
 .wp-editor-container textarea.wp-editor-area {
-        width: 99.9%;
+        width: 100%;
+        margin: 0;
         -webkit-box-shadow: none;
         box-shadow: none;
 }