Index: modules/forum/forum.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/forum/forum.module,v
retrieving revision 1.416
diff -u -p -r1.416 forum.module
--- modules/forum/forum.module	30 Aug 2007 18:58:12 -0000	1.416
+++ modules/forum/forum.module	3 Sep 2007 15:18:55 -0000
@@ -346,7 +346,8 @@ function forum_form_alter(&$form, $form_
       $form['hierarchy'] = array('#type' => 'value', '#value' => 1);
       unset($form['relations']);
       unset($form['tags']);
-      unset($form['multiple']);
+      unset($form['multiple']);
+      unset($form['delete']);
       $form['required'] = array('#type' => 'value', '#value' => 1);
     }
   }
Index: modules/forum/forum.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/forum/forum.install,v
retrieving revision 1.8
diff -u -p -r1.8 forum.install
--- modules/forum/forum.install	2 Jul 2007 17:08:35 -0000	1.8
+++ modules/forum/forum.install	3 Sep 2007 15:18:55 -0000
@@ -1,6 +1,6 @@
 <?php
 // $Id: forum.install,v 1.8 2007/07/02 17:08:35 dries Exp $
-
+
 /**
  * Implementation of hook_install().
  */
@@ -51,3 +51,16 @@ function forum_uninstall() {
   variable_del('forum_block_num_0');
   variable_del('forum_block_num_1');
 }
+
+/**
+ * Implementation of hook_enable.
+ * See http://drupal.org/node/172633
+ */
+function forum_enable() {
+  $vid = variable_get('forum_nav_vocabulary', '');
+  $vocabularies = taxonomy_get_vocabularies();
+  if (!array_key_exists($vid, $vocabularies)) {
+  	forum_install(); // in this version, it does exactly what is needed
+  	drupal_set_message(t('The vocabulary used by the forum module was missing and had to be created anew.'), 'status');
+  }
+}