diff --git a/src/dock_gui.cpp b/src/dock_gui.cpp
--- a/src/dock_gui.cpp
+++ b/src/dock_gui.cpp
@@ -288,7 +288,7 @@ static const WindowDesc _build_docks_too
 	WDP_ALIGN_TBR, 22, 160, 36, 160, 36,
 	WC_BUILD_TOOLBAR, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON | WDF_CONSTRUCTION,
-	NULL, _nested_build_docks_toolbar_widgets, lengthof(_nested_build_docks_toolbar_widgets)
+	_nested_build_docks_toolbar_widgets, lengthof(_nested_build_docks_toolbar_widgets)
 );
 
 void ShowBuildDocksToolbar()
@@ -324,7 +324,7 @@ static const WindowDesc _build_docks_sce
 	WDP_AUTO, WDP_AUTO, 115, 36, 115, 36,
 	WC_SCEN_BUILD_TOOLBAR, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON | WDF_CONSTRUCTION,
-	NULL, _nested_build_docks_scen_toolbar_widgets, lengthof(_nested_build_docks_scen_toolbar_widgets)
+	_nested_build_docks_scen_toolbar_widgets, lengthof(_nested_build_docks_scen_toolbar_widgets)
 );
 
 void ShowBuildDocksScenToolbar()
@@ -421,7 +421,7 @@ static const WindowDesc _build_dock_stat
 	WDP_AUTO, WDP_AUTO, 148, 75, 148, 75,
 	WC_BUILD_STATION, WC_BUILD_TOOLBAR,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_CONSTRUCTION,
-	NULL, _nested_build_dock_station_widgets, lengthof(_nested_build_dock_station_widgets)
+	_nested_build_dock_station_widgets, lengthof(_nested_build_dock_station_widgets)
 );
 
 static void ShowBuildDockStationPicker(Window *parent)
@@ -507,7 +507,7 @@ static const WindowDesc _build_docks_dep
 	WDP_AUTO, WDP_AUTO, 204, 86, 204, 86,
 	WC_BUILD_DEPOT, WC_BUILD_TOOLBAR,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_CONSTRUCTION,
-	NULL, _nested_build_docks_depot_widgets, lengthof(_nested_build_docks_depot_widgets)
+	_nested_build_docks_depot_widgets, lengthof(_nested_build_docks_depot_widgets)
 );