Index: modules/system/system.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.admin.inc,v
retrieving revision 1.283
diff -u -p -r1.283 system.admin.inc
--- modules/system/system.admin.inc	18 May 2010 18:11:13 -0000	1.283
+++ modules/system/system.admin.inc	21 May 2010 05:47:20 -0000
@@ -97,12 +97,15 @@ function system_admin_config_page() {
       }
       $block = $item;
       $block['content'] = '';
-      $block['show'] = TRUE;
       if ($item['block_callback'] && function_exists($item['block_callback'])) {
         $function = $item['block_callback'];
         $block['content'] .= $function();
       }
       $block['content'] .= theme('admin_block_content', array('content' => system_admin_menu_block($item)));
+      if (!empty($block['content'])) {
+        $block['show'] = TRUE;
+      }
+
       // Prepare for sorting as in function _menu_tree_check_access().
       // The weight is offset so it is always positive, with a uniform 5-digits.
       $blocks[(50000 + $item['weight']) . ' ' . $item['title'] . ' ' . $item['mlid']] = $block;