diff -u b/core/misc/ajax.js b/core/misc/ajax.js
--- b/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -1114,15 +1114,12 @@
       if ($new_content.parents('html').length > 0) {
         // Apply any settings from the returned JSON if available.
         settings = response.settings || ajax.settings || drupalSettings;
-        if (method === 'replaceWith') {
-          Drupal.attachBehaviors($wrapper.get(0), settings);
-        }
-        else {
-          // Attach behaviors to all element nodes.
-          $wrapper.children().each(function () {
+        // Attach behaviors to all element nodes.
+        $new_content.each(function () {
+          if (this.nodeType === Node.ELEMENT_NODE) {
             Drupal.attachBehaviors(this, settings);
-          });
-        }
+          }
+        });
       }
     },