diff --git a/core/modules/filter/filter.filter_html.admin.js b/core/modules/filter/filter.filter_html.admin.js
index 73bfc08..aac7376 100644
--- a/core/modules/filter/filter.filter_html.admin.js
+++ b/core/modules/filter/filter.filter_html.admin.js
@@ -195,7 +195,7 @@
         else {
           var requiredAttributes = editorRequiredTags[tag].restrictedTags.allowed.attributes;
           var allowedAttributes = userAllowedTags[tag].restrictedTags.allowed.attributes;
-          var needsAdditionalAttributes= requiredAttributes.length && _.difference(requiredAttributes, allowedAttributes).length;
+          var needsAdditionalAttributes = requiredAttributes.length && _.difference(requiredAttributes, allowedAttributes).length;
           var requiredClasses = editorRequiredTags[tag].restrictedTags.allowed.classes;
           var allowedClasses = userAllowedTags[tag].restrictedTags.allowed.classes;
           var needsAdditionalClasses = requiredClasses.length && _.difference(requiredClasses, allowedClasses).length;