diff --git a/template.php b/template.php
index 06d4f6c..b3a4209 100644
--- a/template.php
+++ b/template.php
@@ -522,7 +522,11 @@ function zen_form_node_form_alter(&$form, &$form_state, $form_id) {
     if (strpos($item, 'field_') === 0) {
       if (!empty($form[$item]['#attributes']['class'])) {
         foreach ($form[$item]['#attributes']['class'] as &$class) {
-          if (strpos($class, 'field-type-') === 0 || strpos($class, 'field-name-') === 0) {
+          // Replace field type and field name classes, but do not replace
+          // the "field-type-text-with-summary" class since it used by the
+          // Text module's JavaScript in order to make the "Edit summary" link
+          // work correctly.
+          if ($class != 'field-type-text-with-summary' && (strpos($class, 'field-type-') === 0 || strpos($class, 'field-name-') === 0)) {
             // Make the class different from that used in theme_field().
             $class = 'form-' . $class;
           }