diff --git a/framework/core/less/forum/discussion.less b/framework/core/less/forum/discussion.less
index f7c361b31..f74fc07c5 100644
--- a/framework/core/less/forum/discussion.less
+++ b/framework/core/less/forum/discussion.less
@@ -61,6 +61,7 @@
     & > ul {
       position: fixed;
       margin-top: 30px;
+      z-index: 1;
 
       & > li {
         margin-bottom: 10px;