diff --git a/www/pad/app-pad.less b/www/pad/app-pad.less
index b413eed6a..489cbb17d 100644
--- a/www/pad/app-pad.less
+++ b/www/pad/app-pad.less
@@ -27,6 +27,7 @@ body.cp-app-pad {
     #cp-app-pad-toc {
         @toc-level-indent: 15px;
 
+        overflow-y: auto;
         margin-top: 10px;
         margin-left: 10px;
         width: 200px;