multigroup + modalnoderef

It should, but I'm not sure as I'm not using mutigroup and modal_noderef anymore for now. And well for the patch, you could apply this part:

--- modal_noderef.module
+++ modal_noderef.module	(working)
@@ -35,7 +35,10 @@ function modal_noderef_form_alter(&$form
       $form['#submit'][] = '_modal_noderef_modal_submit';
     }
     else {
-      _modal_noderef_add_link($form, $form['type']['#value']);
+      if (!isset($form['#after_build'])) {
+        $form['#after_build'] = array();
+      }
+      $form['#after_build'][] = 'modal_noderef_add_link_form_after_build';
     }
   }
 }
@@ -63,6 +66,12 @@ function modal_noderef_nodeapi(&$node, $
   }
 }
 
+function modal_noderef_add_link_form_after_build($form, &$form_state) {
+   _modal_noderef_add_link($form, $form['type']['#value']);
+   return $form;
+}
+
+

So you don't erase other possible after_build calls that could exist.

The other bit of the patch is only needed when using multigroups and there's no stable release yet so...