From cd9fa75ede50a6259ac9cdfb1f2d409add932927 Mon Sep 17 00:00:00 2001
From: "alexey.lysiuk" <alexey.lysiuk@gmail.com>
Date: Tue, 15 Jan 2019 16:22:25 +0200
Subject: [PATCH] - fixed potentially missing event handlers

Event handlers linked list might skip an entry if its order was in a middle of existing handlers

https://forum.zdoom.org/viewtopic.php?t=63258
---
 src/events.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/events.cpp b/src/events.cpp
index b67630eac..e85706a85 100755
--- a/src/events.cpp
+++ b/src/events.cpp
@@ -75,6 +75,11 @@ bool E_RegisterHandler(DStaticEventHandler* handler)
 	{
 		// if before is not null, link it before the existing handler.
 		// note that before can be first handler, check for this.
+		if (before->prev != nullptr)
+		{
+			before->prev->next = handler;
+			GC::WriteBarrier(before->prev, handler);
+		}
 		handler->next = before;
 		GC::WriteBarrier(handler, before);
 		handler->prev = before->prev;