Index: modules/field/field.form.inc
=========================================================
--- modules/field/field.form.inc	(revision 1.14)
+++ modules/field/field.form.inc	Mon Aug 17 12:24:12 PDT 2009
@@ -191,7 +191,10 @@
         // Submit callback for disabled JavaScript.
         '#submit' => array('field_add_more_submit'),
         '#ajax' => array(
-          'path' => 'field/js_add_more/' . $bundle_name_url_css . '/' . $field_name_url_css,
+          // @todo : Once 'callback' is accepted as the prefered implementation,
+          // remove the 'path' attribute.
+          //'path' => 'field/js_add_more/' . $bundle_name_url_css . '/' . $field_name_url_css,
+          'callback' => 'field_add_more_js',
           'wrapper' => $field_name_url_css . '-wrapper',
           'method' => 'replace',
           'effect' => 'fade',
@@ -333,6 +336,37 @@
 /**
  * Menu callback for AHAH addition of new empty widgets.
  */
+// @todo : Waiting on http://drupal.org/node/370537 to figure out validation
+function field_add_more_js($form, $form_state) {
+  $field_name = $form_state['clicked_button']['#field_name'];
+  $bundle_name = $form_state['clicked_button']['#bundle'];
+  
+  // Retrieve field information.
+  $field = $form['#fields'][$field_name]['field'];
+  $instance = $form['#fields'][$field_name]['instance'];
+  $form_path = $form['#fields'][$field_name]['form_path'];
+
+  // Fetch the form element that needs rendering.
+  $field_form = $form;
+  foreach ($form_path as $key) {
+    $field_form = $field_form[$key];
+  }
+  
+  // Add a DIV around the new field to receive the AJAX effect.
+  $delta = max(element_children($field_form));
+  $field_form[$delta]['#prefix'] = '<div class="ajax-new-content">' . (isset($field_form[$delta]['#prefix']) ? $field_form[$delta]['#prefix'] : '');
+  $field_form[$delta]['#suffix'] = (isset($field_form[$delta]['#suffix']) ? $field_form[$delta]['#suffix'] : '') . '</div>';
+  // Prevent duplicate wrapper.
+  // @todo : why does it work when we don't unset, but doesn't work when we do unset? this needs investigation.
+  //unset($field_form['#prefix'], $field_form['#suffix']);
+
+  // Rendering may produce status messages, so render first.
+  $output = drupal_render($field_form);
+  return theme('status_messages') . $output;
+}
+
+// @todo : Remove this old implementation once the new one is accepted.
+/*
 function field_add_more_js($bundle_name, $field_name) {
   // Arguments are coming from the url, so we translate back dashes.
   $field_name = str_replace('-', '_', $field_name);
@@ -440,3 +474,4 @@
   $commands[] = ajax_command_replace(NULL, $output);
   ajax_render($commands);
 }
+*/