--- taxonomy.module_cvs	2006-07-19 01:47:17.000000000 +0100
+++ taxonomy.module_new	2006-07-19 01:48:51.000000000 +0100
@@ -671,7 +671,7 @@
         $form['taxonomy'][$vocabulary->vid]['#required'] = $vocabulary->required;
       }
     }
-    if (isset($form['taxonomy'])) {
+    if (is_array($form['taxonomy']) && count($form['taxonomy']) > 1) {
       $form['taxonomy'] += array('#type' => 'fieldset', '#title' => t('Categories'), '#collapsible' => TRUE, '#collapsed' => FALSE, '#tree' => TRUE, '#weight' => -3);
     }
   }