diff --git a/src/signs_gui.cpp b/src/signs_gui.cpp
--- a/src/signs_gui.cpp
+++ b/src/signs_gui.cpp
@@ -206,7 +206,7 @@ static const WindowDesc _sign_list_desc(
 	WDP_AUTO, WDP_AUTO, 0, 0, 358, 138,
 	WC_SIGN_LIST, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON | WDF_RESIZABLE,
-	NULL, _nested_sign_list_widgets, lengthof(_nested_sign_list_widgets)
+	_nested_sign_list_widgets, lengthof(_nested_sign_list_widgets)
 );
 
 
@@ -404,7 +404,7 @@ static const WindowDesc _query_sign_edit
 	190, 170, 260, 42, 260, 42,
 	WC_QUERY_STRING, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_CONSTRUCTION | WDF_UNCLICK_BUTTONS,
-	NULL, _nested_query_sign_edit_widgets, lengthof(_nested_query_sign_edit_widgets)
+	_nested_query_sign_edit_widgets, lengthof(_nested_query_sign_edit_widgets)
 );
 
 void HandleClickOnSign(const Sign *si)