diff --git a/app/assets/stylesheets/pages/issuable.scss b/app/assets/stylesheets/pages/issuable.scss
index 5bf44c1cdb6ed6a3eeaf0d2fe010db8837c760b8..9397e1a662663e3dade895f35a788179ad383f6b 100644
--- a/app/assets/stylesheets/pages/issuable.scss
+++ b/app/assets/stylesheets/pages/issuable.scss
@@ -128,6 +128,7 @@
   top: 58px;
   bottom: 0;
   right: 0;
+  z-index: 10;
   transition: width .3s;
   background: $gray-light;
   padding: 10px 20px;