diff --git a/tests/reftests/reset-to-defaults.css b/tests/reftests/reset-to-defaults.css
index af1fe41f72..671b971b8a 100644
--- a/tests/reftests/reset-to-defaults.css
+++ b/tests/reftests/reset-to-defaults.css
@@ -55,4 +55,5 @@
 
   -GtkWidget-focus-line-width: 0;
   -GtkWidget-focus-padding: 0;
+  -GtkNotebook-initial-gap: 0;
 }