From b17f738f13cf5f8ece3602e72ef2e0a2c48bed5b Mon Sep 17 00:00:00 2001
From: biwa <6475593+biwa@users.noreply.github.com>
Date: Fri, 17 Jul 2020 20:35:59 +0200
Subject: [PATCH] Fixed a crash when highlighting undefined things

---
 Source/Plugins/BuilderModes/General/Association.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Source/Plugins/BuilderModes/General/Association.cs b/Source/Plugins/BuilderModes/General/Association.cs
index dd2b9a9..169c36d 100644
--- a/Source/Plugins/BuilderModes/General/Association.cs
+++ b/Source/Plugins/BuilderModes/General/Association.cs
@@ -138,7 +138,11 @@ namespace CodeImp.DoomBuilder.BuilderModes
 				center = t.Position;
 
 				ThingTypeInfo ti = General.Map.Data.GetThingInfoEx(t.Type);
-				directlinktype = ti.ThingLink;
+
+				if (ti != null)
+					directlinktype = ti.ThingLink;
+				else
+					directlinktype = 0;
 
 				type = UniversalType.ThingTag;
 				tags = new HashSet<int>(new int[] { t.Tag });