diff --git a/src/main_gui.cpp b/src/main_gui.cpp
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -207,7 +207,7 @@ static const struct NWidgetPart _nested_
 };
 
 static WindowDesc _main_window_desc(
-	WDP_MANUAL, 0, 0,
+	WDP_MANUAL, NULL, 0, 0,
 	WC_MAIN_WINDOW, WC_NONE,
 	0,
 	_nested_main_window_widgets, lengthof(_nested_main_window_widgets)