diff --git a/src/windows/custom_currency.c b/src/windows/custom_currency.c
index ad6aea07b7..ed74959dd3 100644
--- a/src/windows/custom_currency.c
+++ b/src/windows/custom_currency.c
@@ -16,6 +16,7 @@
 
 #include "../localisation/localisation.h"
 #include "../interface/widget.h"
+#include "../interface/window.h"
 #include "../config.h"
 #include "dropdown.h"