diff --git a/src/cheat_gui.cpp b/src/cheat_gui.cpp
--- a/src/cheat_gui.cpp
+++ b/src/cheat_gui.cpp
@@ -66,8 +66,9 @@ static int32 ClickChangeCompanyCheat(int
  */
 static int32 ClickSetProdCheat(int32 p1, int32 p2)
 {
-	SetWindowClassesDirty(WC_INDUSTRY_VIEW);
-	return p1;
+	_cheats.setup_prod.value = p1;
+	InvalidateWindowClassesData(WC_INDUSTRY_VIEW);
+	return _cheats.setup_prod.value;
 }
 
 /**