diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index 6d9100a1643..9269272d484 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -777,7 +777,8 @@ function file_ajax_upload() {
     $form['#suffix'] .= '<span class="ajax-new-content"></span>';
   }
 
-  $output = theme('status_messages') . drupal_render($form);
+  $form['#prefix'] .= theme('status_messages');
+  $output = drupal_render($form);
   $js = drupal_add_js();
   $settings = drupal_merge_js_settings($js['settings']['data']);
 
diff --git a/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php b/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php
index d749f578a2d..f14a637f159 100644
--- a/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php
+++ b/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php
@@ -310,4 +310,51 @@ class FileFieldWidgetTest extends FileFieldTestBase {
     $this->assertResponse(403, t('Confirmed that access is denied for the file without the needed permission.'));
   }
 
+  /**
+   * Tests validation with the Upload button.
+   */
+  function testWidgetValidation() {
+    $type_name = 'article';
+    $field_name = strtolower($this->randomName());
+    $this->createFileField($field_name, $type_name);
+    $this->updateFileField($field_name, $type_name, array('file_extensions' => 'txt'));
+
+    foreach (array('nojs', 'js') as $type) {
+      // Create node and prepare files for upload.
+      $node = $this->drupalCreateNode(array('type' => 'article'));
+      $nid = $node->nid;
+      $this->drupalGet("node/$nid/edit");
+      $test_file_text = $this->getTestFile('text');
+      $test_file_image = $this->getTestFile('image');
+      $field = field_info_field($field_name);
+      $name = 'files[' . $field_name . '_' . LANGUAGE_NOT_SPECIFIED . '_0]';
+
+      // Upload file with incorrect extension, check for validation error.
+      $edit[$name] = drupal_realpath($test_file_image->uri);
+      switch ($type) {
+        case 'nojs':
+          $this->drupalPost(NULL, $edit, t('Upload'));
+          break;
+        case 'js':
+          $button = $this->xpath('//input[@type="submit" and @value="' . t('Upload') . '"]');
+          $this->drupalPostAJAX(NULL, $edit, array((string) $button[0]['name'] => (string) $button[0]['value']));
+          break;
+      }
+      $error_message = t('Only files with the following extensions are allowed: %files-allowed.', array('%files-allowed' => 'txt'));
+      $this->assertRaw($error_message, t('Validation error when file with wrong extension uploaded (JSMode=%type).', array('%type' => $type)));
+
+      // Upload file with correct extension, check that error message is removed.
+      $edit[$name] = drupal_realpath($test_file_text->uri);
+      switch ($type) {
+        case 'nojs':
+          $this->drupalPost(NULL, $edit, t('Upload'));
+          break;
+        case 'js':
+          $button = $this->xpath('//input[@type="submit" and @value="' . t('Upload') . '"]');
+          $this->drupalPostAJAX(NULL, $edit, array((string) $button[0]['name'] => (string) $button[0]['value']));
+          break;
+      }
+      $this->assertNoRaw($error_message, t('Validation error removed when file with correct extension uploaded (JSMode=%type).', array('%type' => $type)));
+    }
+  }
 }