diff --git a/core/includes/common.inc b/core/includes/common.inc
index e975823..ae3f6ac 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -533,6 +533,35 @@ function drupal_get_destination() {
 }
 
 /**
+ * Utility method to get the normalized type of the current request.
+ *
+ * Fetches the ContentNegotiation and Request objects from the current container
+ * and returns the associated request content type. The normalized type is a
+ * short, lowercase version of the format, such as 'html', 'json' or 'atom'.
+ *
+ * @return string
+ *   The request type
+ */
+function drupal_get_request_content_type() {
+  $type = &drupal_static(__FUNCTION__);
+
+  if (isset($type)) {
+    return $type;
+  }
+  else {
+    $container = drupal_container();
+    if ($container->has('request') &&
+        $container->has('content_negotiation')) {
+      $type = $container->get('content_negotiation')->getContentType($container->get('request'));
+    }
+    else {
+      $type = FALSE;
+    }
+  }
+  return $type;
+}
+
+/**
  * Parses a system URL string into an associative array suitable for url().
  *
  * This function should only be used for URLs that have been generated by the
@@ -3891,9 +3920,9 @@ function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALS
   if (!empty($items)) {
     // Sort the JavaScript files so that they appear in the correct order.
     uasort($items, 'drupal_sort_css_js');
-
-    // Don't add settings if there is no other JS on the page.
-    if (!empty($items['settings'])) {
+    // Don't add settings if there is no other JavaScript on the page, unless
+    // this is an ajax request.
+    if (!empty($items['settings']) || drupal_get_request_content_type() == 'ajax') {
       global $theme_key;
       // Provide the page with information about the theme that's used, so that a
       // later AJAX request can be rendered using the same theme.
@@ -3910,12 +3939,14 @@ function drupal_get_js($scope = 'header', $javascript = NULL, $skip_alter = FALS
       unset($setting['ajaxPageState']['js']['settings']);
 
       // Provide the page with information about the individual CSS files used,
-      // information not otherwise available when CSS aggregation is enabled. The
-      // setting is attached later in this function, but is set here, so that CSS
-      // files removed below are still considered "used" and prevented from being
-      // added in a later AJAX request.
-      // Skip if no files were added to the page otherwise jQuery.extend() will overwrite
-      // the Drupal.settings.ajaxPageState.css object with an empty array.
+      // information not otherwise available when CSS aggregation is enabled.
+      // The setting is attached later in this function, but is set here, so
+      // that CSS files removed in drupal_process_attached() are still
+      // considered "used" and prevented from being added in a later AJAX
+      // request.
+      // Skip if no files were added to the page otherwise jQuery.extend() will
+      // overwrite the Drupal.settings.ajaxPageState.css object with an empty
+      // array.
       $css = drupal_add_css();
       if (!empty($css)) {
         // Cast the array to an object to be on the safe side even if not empty.
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
index d9e50db..cfb82f6 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/JavaScriptTest.php
@@ -509,7 +509,7 @@ class JavaScriptTest extends WebTestBase {
     $libraries = drupal_get_library('common_test');
     $this->assertTrue(isset($libraries['jquery.farbtastic']), t('Retrieved all module libraries.'));
     // Retrieve all libraries for a module not implementing hook_library_info().
-    // Note: This test installs tracker module.
+    // Note: This test installs language module.
     $libraries = drupal_get_library('language');
     $this->assertEqual($libraries, array(), t('Retrieving libraries from a module not implementing hook_library_info() returns an emtpy array.'));
 
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index b13cf83..2adc714 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1212,7 +1212,7 @@ function _system_batch_theme() {
  * Implements hook_library_info().
  */
 function system_library_info() {
-  // Drupal specific javascript.
+  // Drupal specific JavaScript.
   $libraries['drupal'] = array(
     'title' => 'Drupal',
     'version' => VERSION,
@@ -2010,7 +2010,10 @@ function system_library_info() {
  * Implements hook_js_alter().
  */
 function system_js_alter(&$javascript) {
-  // Add configuration only if there are settings added to the page.
+  // Add configuration only if there are settings added to the page. This is
+  // only necessary for JavaScript that is added through drupal_add_js(),
+  // JavaScript that is added as a library would nominate its dependency on
+  // drupal.settings.
   if (!empty($javascript['settings'])) {
     $javascript['settings'] += array(
       'type' => 'setting',
diff --git a/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module b/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module
index fc6da40..8e9545f 100644
--- a/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module
+++ b/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module
@@ -506,6 +506,7 @@ function ajax_forms_test_lazy_load_form($form, &$form_state) {
 function ajax_forms_test_lazy_load_form_submit($form, &$form_state) {
   if ($form_state['values']['add_files']) {
     drupal_add_library('system', 'drupal.system');
+    drupal_add_css(drupal_get_path('module', 'system') . '/system.admin.css');
     drupal_add_js(array('ajax_forms_test_lazy_load_form_submit' => 'executed'), 'setting');
   }
   $form_state['rebuild'] = TRUE;
diff --git a/core/modules/taxonomy/taxonomy.module b/core/modules/taxonomy/taxonomy.module
index 9eaa156..ce8b274 100644
--- a/core/modules/taxonomy/taxonomy.module
+++ b/core/modules/taxonomy/taxonomy.module
@@ -1704,9 +1704,9 @@ function taxonomy_entity_query_alter($query) {
   }
 }
 
-  /**
-   * Implements hook_library_info().
-   */
+/**
+ * Implements hook_library_info().
+ */
 function taxonomy_library_info() {
   $libraries['drupal.taxonomy'] = array(
     'title' => 'Taxonomy',