diff --git a/app/assets/stylesheets/pages/issuable.scss b/app/assets/stylesheets/pages/issuable.scss
index aa04e490649878213a2ba8b6aebd8a0ba65516bc..eb269df46fe7562dc1bda765bbaa5477484efdb7 100644
--- a/app/assets/stylesheets/pages/issuable.scss
+++ b/app/assets/stylesheets/pages/issuable.scss
@@ -211,6 +211,10 @@
     -webkit-overflow-scrolling: touch;
   }
 
+  &.affix-top .issuable-sidebar {
+    height: 100%;
+  }
+
   &.right-sidebar-expanded {
     width: $gutter_width;