diff --git a/src/widget_type.h b/src/widget_type.h
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -1155,6 +1155,6 @@ static inline NWidgetPart NWidgetFunctio
 NWidgetContainer *MakeNWidgets(const NWidgetPart *parts, int count, int *biggest_index, NWidgetContainer *container);
 NWidgetContainer *MakeWindowNWidgetTree(const NWidgetPart *parts, int count, int *biggest_index, NWidgetStacked **shade_select);
 
-NWidgetBase *MakeCompanyButtonRows(int *biggest_index, int widget_first, int widget_last, int max_length, StringID button_tooltip);
+NWidgetBase *MakeCompanyButtonRows(int *biggest_index, int widget_first, int widget_last, Colours button_colour, int max_length, StringID button_tooltip);
 
 #endif /* WIDGET_TYPE_H */