diff --git a/terraform_gui.c b/terraform_gui.c
index a00fda571d..e66fadb827 100644
--- a/terraform_gui.c
+++ b/terraform_gui.c
@@ -36,7 +36,7 @@ static const uint16 _terraform_keycodes[] = {
 	'3',
 	'4',
 	'5',
-	'6',
+	0,
 	'7',
 };