diff -rupN computed_field.module computed_field.module
--- computed_field.module	2009-01-08 12:08:19.000000000 +0100
+++ computed_field.module	2009-01-08 12:15:43.000000000 +0100
@@ -325,3 +325,17 @@ function computed_field_token_values($ty
     return $tokens;
   }
 }
+
+/**
+ * Implementation of hook_content_multigroup_allowed_widgets().
+ */
+function computed_field_content_multigroup_allowed_widgets() {
+  return array('computed');
+}
+
+/**
+ * Implementation of hook_content_multigroup_no_remove_widgets().
+ */
+function computed_field_content_multigroup_no_remove_widgets() {
+  return array('computed');
+}