From 0c5472043e6da6dd4e0ad59318ccfca3534c0234 Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver@mutability.co.uk>
Date: Wed, 22 Mar 2017 22:29:02 +0000
Subject: [PATCH] Don't explode on map pan after deselecting an aircraft that
 was being followed.

---
 public_html/script.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/public_html/script.js b/public_html/script.js
index bc3fcbb..b505293 100644
--- a/public_html/script.js
+++ b/public_html/script.js
@@ -580,8 +580,9 @@ function initialize_map() {
                 if (FollowSelected) {
                         // On manual navigation, disable follow
                         var selected = Planes[SelectedPlane];
-                        if (Math.abs(center[0] - selected.position[0]) > 0.0001 &&
-                            Math.abs(center[1] - selected.position[1]) > 0.0001) {
+                        if (typeof selected === 'undefined' ||
+                            (Math.abs(center[0] - selected.position[0]) > 0.0001 &&
+                             Math.abs(center[1] - selected.position[1]) > 0.0001)) {
                                 FollowSelected = false;
                                 refreshSelected();
                                 refreshHighlighted();