diff --git a/app/assets/stylesheets/sections/header.scss b/app/assets/stylesheets/sections/header.scss
index db419f76532..f71b62ace9c 100644
--- a/app/assets/stylesheets/sections/header.scss
+++ b/app/assets/stylesheets/sections/header.scss
@@ -4,6 +4,7 @@
  */
 header {
   &.navbar-gitlab {
+    z-index: 100;
     margin-bottom: 0;
     min-height: 40px;
     border: none;
@@ -82,8 +83,6 @@ header {
     }
   }
 
-  z-index: 10;
-
   .container {
     width: 100% !important;
     padding-left: 0px;
diff --git a/app/assets/stylesheets/sections/sidebar.scss b/app/assets/stylesheets/sections/sidebar.scss
index 51d6b2c920c..fdf9eb86d46 100644
--- a/app/assets/stylesheets/sections/sidebar.scss
+++ b/app/assets/stylesheets/sections/sidebar.scss
@@ -3,6 +3,7 @@
 }
 
 .sidebar-wrapper {
+  z-index: 99;
   overflow-y: auto;
   background: #F5F5F5;
 }