diff --git a/src/terraform_gui.cpp b/src/terraform_gui.cpp
--- a/src/terraform_gui.cpp
+++ b/src/terraform_gui.cpp
@@ -344,7 +344,7 @@ static const WindowDesc _terraform_desc(
 	WDP_ALIGN_TBR, 22 + 36, 158, 36, 158, 36,
 	WC_SCEN_LAND_GEN, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON | WDF_CONSTRUCTION,
-	NULL, _nested_terraform_widgets, lengthof(_nested_terraform_widgets)
+	_nested_terraform_widgets, lengthof(_nested_terraform_widgets)
 );
 
 Window *ShowTerraformToolbar(Window *link)
@@ -777,7 +777,7 @@ static const WindowDesc _scen_edit_land_
 	WDP_AUTO, WDP_AUTO, 163, 103, 163, 103,
 	WC_SCEN_LAND_GEN, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON | WDF_CONSTRUCTION,
-	NULL, _nested_scen_edit_land_gen_widgets, lengthof(_nested_scen_edit_land_gen_widgets)
+	_nested_scen_edit_land_gen_widgets, lengthof(_nested_scen_edit_land_gen_widgets)
 );
 
 Window *ShowEditorTerraformToolbar()