diff --git a/plugins/chat/assets/stylesheets/common/chat-side-panel-resizer.scss b/plugins/chat/assets/stylesheets/common/chat-side-panel-resizer.scss
index 291d9e53c1b..17a1de45085 100644
--- a/plugins/chat/assets/stylesheets/common/chat-side-panel-resizer.scss
+++ b/plugins/chat/assets/stylesheets/common/chat-side-panel-resizer.scss
@@ -4,7 +4,7 @@
   left: -3px;
   width: 5px;
   position: absolute;
-  z-index: z("max");
+  z-index: calc(z("header") - 1);
   transition: background-color 0.15s 0.15s;
   background-color: transparent;