diff --git a/gui/Main.hs b/gui/Main.hs
index 2f5620e..5e0619e 100644
--- a/gui/Main.hs
+++ b/gui/Main.hs
@@ -1,3 +1,4 @@
+-- This file is formatted with Ormolu
 {-# LANGUAGE BlockArguments #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs #-}