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 61186aea264..da70de0ec0b 100644
--- a/plugins/chat/assets/stylesheets/common/chat-side-panel-resizer.scss
+++ b/plugins/chat/assets/stylesheets/common/chat-side-panel-resizer.scss
@@ -3,7 +3,7 @@
   bottom: 0;
 
   position: absolute;
-  z-index: calc(z("header") - 1);
+  z-index: z("composer", "content") - 1;
   transition: background-color 0.15s 0.15s;
   background-color: transparent;