diff --git a/src/engine_gui.cpp b/src/engine_gui.cpp
--- a/src/engine_gui.cpp
+++ b/src/engine_gui.cpp
@@ -127,7 +127,7 @@ static const WindowDesc _engine_preview_
 	WDP_CENTER, WDP_CENTER, 300, 192, 300, 192,
 	WC_ENGINE_PREVIEW, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_CONSTRUCTION,
-	NULL, _nested_engine_preview_widgets, lengthof(_nested_engine_preview_widgets)
+	_nested_engine_preview_widgets, lengthof(_nested_engine_preview_widgets)
 );