From cce665c07b5c162f16ea53663647d03157a15021 Mon Sep 17 00:00:00 2001
From: Jonathan G Rennison <j.g.rennison@gmail.com>
Date: Sat, 29 Jan 2022 13:22:03 +0000
Subject: [PATCH] Fix #9802: Assertion failure in BuildRailWaypointWindow
 constructor

---
 src/rail_gui.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index c54e172a0c..c9b04ee29d 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -2015,6 +2015,7 @@ struct BuildRailWaypointWindow : PickerWindowBase {
 		this->FinishInitNested(TRANSPORT_RAIL);
 
 		matrix->SetCount(_waypoint_count);
+		if (_cur_waypoint_type >= _waypoint_count) _cur_waypoint_type = 0;
 		matrix->SetClicked(_cur_waypoint_type);
 	}