diff --git a/UI/WebServerResources/scss/core/variables.scss b/UI/WebServerResources/scss/core/variables.scss
index 0526da2a7..9eb88f01d 100644
--- a/UI/WebServerResources/scss/core/variables.scss
+++ b/UI/WebServerResources/scss/core/variables.scss
@@ -135,6 +135,7 @@ $z-index-tooltip: 100 !default;
 $z-index-dialog: 80 !default;
 $z-index-toast: 90 !default;
 $z-index-bottom-sheet: 70 !default;
+$z-index-scroll-mask: 65 !default;
 $z-index-sidenav: 60 !default;
 $z-index-backdrop: 50 !default;
 $z-index-toolbar: 10 !default;