diff --git a/src/widgets/dropdown.cpp b/src/widgets/dropdown.cpp
--- a/src/widgets/dropdown.cpp
+++ b/src/widgets/dropdown.cpp
@@ -86,7 +86,7 @@ const WindowDesc _dropdown_desc(
 	0, 0, 0, 0, 0, 0, // x/y position not used.
 	WC_DROPDOWN_MENU, WC_NONE,
 	WDF_DEF_WIDGET,
-	NULL, _nested_dropdown_menu_widgets, lengthof(_nested_dropdown_menu_widgets)
+	_nested_dropdown_menu_widgets, lengthof(_nested_dropdown_menu_widgets)
 );
 
 /** Drop-down menu window */