diff --git a/windows/tariffcalculator.pas b/windows/tariffcalculator.pas
index 639ee6f..0464ade 100644
--- a/windows/tariffcalculator.pas
+++ b/windows/tariffcalculator.pas
@@ -1,6 +1,6 @@
 unit TariffCalculator;
 
-{$mode ObjFPC}{$H+}
+{$mode ObjFPC}{$H-}
 
 interface