diff --git a/core/modules/config/config.admin.inc b/core/modules/config/config.admin.inc
index 718c773..284fbb1 100644
--- a/core/modules/config/config.admin.inc
+++ b/core/modules/config/config.admin.inc
@@ -6,6 +6,8 @@
  */
 
 use Drupal\Core\Config\StorageInterface;
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\OpenModalDialogCommand;
 
 /**
  * Helper function to construct the storage changes in a configuration synchronization form.
@@ -37,6 +39,9 @@ function config_admin_sync_form(array &$form, array &$form_state, StorageInterfa
     return $form;
   }
 
+  // Add the AJAX library to the form.
+  $form['#attached']['library'][] = array('system', 'drupal.ajax');
+
   foreach ($config_changes as $config_change_type => $config_files) {
     if (empty($config_files)) {
       continue;
@@ -70,7 +75,9 @@ function config_admin_sync_form(array &$form, array &$form_state, StorageInterfa
       $links['view_diff'] = array(
         'title' => t('View differences'),
         'href' => 'admin/config/development/sync/diff/' . $config_file,
-        'ajax' => array('dialog' => array('modal' =>TRUE, 'width' => '700px')),
+        'attributes' => array(
+          'class' => array('use-ajax'),
+        ),
       );
       $form[$config_change_type]['list']['#rows'][] = array(
         'name' => $config_file,
@@ -149,12 +156,6 @@ function config_admin_diff_page($config_file) {
   // Add the CSS for the inline diff.
   $output['#attached']['css'][] = drupal_get_path('module', 'system') . '/system.diff.css';
 
-  $output['title'] = array(
-    '#theme' => 'html_tag',
-    '#tag' => 'h3',
-    '#value' => t('View changes of @config_file', array('@config_file' => $config_file)),
-  );
-
   $diff = config_diff($target_storage, $source_storage, $config_file);
   $formatter = new DrupalDiffFormatter();
   $formatter->show_header = FALSE;
@@ -175,10 +176,29 @@ function config_admin_diff_page($config_file) {
     '#type' => 'link',
     '#title' => "Back to 'Synchronize configuration' page.",
     '#href' => 'admin/config/development/sync',
-    '#attributes' => array(
-      'class' => array('dialog-cancel'),
-    ),
   );
 
+  $title = t('View changes of @config_file', array('@config_file' => $config_file));
+
+  // Return AJAX requests as a dialog.
+  if (Drupal::service('request')->isXmlHttpRequest()) {
+    // Add class to the close link.
+    $output['back']['#attributes']['class'][] = 'dialog-cancel';
+
+    $dialog_content = drupal_render($output);
+    $response = new AjaxResponse();
+    $response->addCommand(new OpenModalDialogCommand($title, $dialog_content, array('width' => '700')));
+    return $response;
+  }
+  // Otherwise show the page title as an element.
+  else {
+    $output['title'] = array(
+      '#theme' => 'html_tag',
+      '#tag' => 'h3',
+      '#value' => $title,
+      '#weight' => -10,
+    );
+  }
+
   return $output;
 }