diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 8cf70b9a995..53b08cf5697 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -166,7 +166,6 @@ nav.sub {
 	top: 0;
 	height: 100vh;
 	overflow: auto;
-	z-index: 1;
 }
 
 .sidebar .block > ul > li {