diff -u b/wysiwyg.module b/wysiwyg.module
--- b/wysiwyg.module
+++ b/wysiwyg.module
@@ -341,9 +341,11 @@
       // Check whether the editor requires an inline initialization script.
       if (!empty($editor['init callback'])) {
         // Request global variables from the editor.
-        $init = $editor['init callback']($editor, $library, $profile);
-        if (!empty($init)) {
-          drupal_add_js($init, array('type' => 'inline') + $default_library_options);
+        $init_script = $editor['init callback']($editor, $library, $profile);
+        if (!empty($init_script)) {
+          // ajax_render() ignores inline scripts. We work around that.
+          // @see wysiwyg_js_alter()
+          drupal_add_js($init_script, array('wysiwyg' => 'inline') + $default_library_options);
         }
       }
 
@@ -412,6 +414,19 @@
 }
 
 /**
+ * Implements hook_js_alter().
+ *
+ * @see wysiwyg_load_editor()
+ */
+function wysiwyg_js_alter(&$items) {
+  foreach ($items as &$item) {
+    if (isset($item['wysiwyg'])) {
+      $item['type'] = 'inline';
+    }
+  }
+}
+
+/**
  * Add editor settings for a given input format.
  */
 function wysiwyg_add_editor_settings($profile, $theme) {