diff --git a/modules/system/system.module b/modules/system/system.module
index 40d4269713eec03860343637fb1542e48c3eaa80..e3ebca66dafcfbf24194040dc550987da84424dd 100644
--- a/modules/system/system.module
+++ b/modules/system/system.module
@@ -2371,7 +2371,7 @@ function theme_system_admin_by_module($menu_items) {
     }
   }
 
-  $output = '<div class="admin">';
+  $output = '<div class="admin clear-block">';
   foreach ($container as $id => $data) {
     $output .= '<div class="'. $id .' clear-block">';
     $output .= $data;