diff --git a/frontend/app/app.less b/frontend/app/app.less
index d4ef24a77..c726dbc35 100644
--- a/frontend/app/app.less
+++ b/frontend/app/app.less
@@ -63,6 +63,7 @@ a.plain-link {
         left: 0;
         width: 100%;
         height: 100%;
+        z-index: var(--zindex-app-background);
     }
 }
 
diff --git a/frontend/app/theme.less b/frontend/app/theme.less
index 9af1cf070..3c0c1467e 100644
--- a/frontend/app/theme.less
+++ b/frontend/app/theme.less
@@ -62,6 +62,7 @@
     --zindex-layout-magnified-node: 5;
     --zindex-block-mask-inner: 10;
     --zindex-flash-error-container: 550;
+    --zindex-app-background: -1;
 
     // z-indexes in xterm.css
     // xterm-helpers: 5