diff --git a/src/browser/base/content/zen-styles/zen-browser-ui.css b/src/browser/base/content/zen-styles/zen-browser-ui.css
index a11f08b36..e5d6e20f3 100644
--- a/src/browser/base/content/zen-styles/zen-browser-ui.css
+++ b/src/browser/base/content/zen-styles/zen-browser-ui.css
@@ -46,6 +46,7 @@
 #tabbrowser-tabbox {
   display: flex;
   flex-direction: row;
+  position: relative;
 }
 
 .titlebar-buttonbox-container {