diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -1176,9 +1176,8 @@ struct BuildVehicleWindow : Window {
 
 	virtual void OnResize()
 	{
-		NWidgetCore *nwi = this->GetWidget<NWidgetCore>(BUILD_VEHICLE_WIDGET_LIST);
-		this->vscroll.SetCapacity(nwi->current_y / this->resize.step_height);
-		nwi->widget_data = (this->vscroll.GetCapacity() << MAT_ROW_START) + (1 << MAT_COL_START);
+		this->vscroll.SetCapacityFromWidget(this, BUILD_VEHICLE_WIDGET_LIST);
+		this->GetWidget<NWidgetCore>(BUILD_VEHICLE_WIDGET_LIST)->widget_data = (this->vscroll.GetCapacity() << MAT_ROW_START) + (1 << MAT_COL_START);
 	}
 };