diff --git a/src/order_gui.cpp b/src/order_gui.cpp
index 0721e4d677..832999c9b2 100644
--- a/src/order_gui.cpp
+++ b/src/order_gui.cpp
@@ -562,7 +562,8 @@ private:
 	{
 		int sel = this->vscroll->GetScrolledRowFromWidget(y, this, WID_O_ORDER_LIST, WidgetDimensions::scaled.framerect.top);
 		if (sel == INT_MAX) return INVALID_VEH_ORDER_ID;
-		assert(IsInsideBS(sel, 0, vehicle->GetNumOrders()));
+		/* One past the orders is the 'End of Orders' line. */
+		assert(IsInsideBS(sel, 0, vehicle->GetNumOrders() + 1));
 		return sel;
 	}