diff --git a/src/tilehighlight_func.h b/src/tilehighlight_func.h
--- a/src/tilehighlight_func.h
+++ b/src/tilehighlight_func.h
@@ -16,7 +16,7 @@
 void PlaceProc_DemolishArea(TileIndex tile);
 bool GUIPlaceProcDragXY(ViewportDragDropSelectionProcess proc, TileIndex start_tile, TileIndex end_tile);
 
-bool HandlePlacePushButton(Window *w, int widget, CursorID cursor, HighLightStyle mode);
+bool HandlePlacePushButton(Window *w, WidgetID widget, CursorID cursor, HighLightStyle mode);
 void SetObjectToPlaceWnd(CursorID icon, PaletteID pal, HighLightStyle mode, Window *w);
 void SetObjectToPlace(CursorID icon, PaletteID pal, HighLightStyle mode, WindowClass window_class, WindowNumber window_num);
 void ResetObjectToPlace();