diff --git a/modules/forum/forum.module b/modules/forum/forum.module
index 0dcea5a..f6f6854 100644
--- a/modules/forum/forum.module
+++ b/modules/forum/forum.module
@@ -581,22 +581,26 @@ function forum_field_storage_pre_update($entity_type, $entity, &$skip_fields) {
  * Implements hook_form_alter().
  */
 function forum_form_alter(&$form, $form_state, $form_id) {
-  $vid = variable_get('forum_nav_vocabulary', 0);
-  if (isset($form['vid']) && $form['vid']['#value'] == $vid) {
-    // Hide critical options from forum vocabulary.
-    if ($form_id == 'taxonomy_form_vocabulary') {
-      $form['help_forum_vocab'] = array(
-        '#markup' => t('This is the designated forum vocabulary. Some of the normal vocabulary options have been removed.'),
-        '#weight' => -1,
-      );
-      $form['hierarchy'] = array('#type' => 'value', '#value' => 1);
-      $form['delete']['#access'] = FALSE;
-    }
-    // Hide multiple parents select from forum terms.
-    elseif ($form_id == 'taxonomy_form_term') {
-      $form['advanced']['parent']['#access'] = FALSE;
-    }
-  }
+  // Prevent the user from making changes to the vocab/term that would make it
+  // incompatible with how forum module works.
+  switch($form_id) {
+    case 'taxonomy_form_vocabulary':
+      $vid = variable_get('forum_nav_vocabulary', 0);
+      if (isset($form['vid']) && $form['vid']['#value'] == $vid) {
+        $form['help_forum_vocab'] = array(
+          '#markup' => t('This is the designated forum vocabulary. Some of the normal vocabulary options have been removed.'),
+          '#weight' => -1,
+        );
+        $form['hierarchy'] = array('#type' => 'value', '#value' => 1);
+        $form['delete']['#access'] = FALSE;
+      }
+      break;
+    case 'taxonomy_form_term':
+      $vid = variable_get('forum_nav_vocabulary', 0);
+      if (isset($form['vid']) && $form['vid']['#value'] == $vid) {
+        $form['advanced']['parent']['#access'] = FALSE;
+      }
+      break;
   if (!empty($form['#node_edit_form']) && isset($form['taxonomy_forums'])) {
     $langcode = $form['taxonomy_forums']['#language'];
     // Make the vocabulary required for 'real' forum-nodes.