From 286decbad33b84bb898b52fbd06badc4f31d9d1d Mon Sep 17 00:00:00 2001
From: James Tabor <james.tabor@reactos.org>
Date: Mon, 6 Aug 2012 05:04:15 +0000
Subject: [PATCH] [NtUser] - Fix empty list error and add a note.

svn path=/trunk/; revision=57047
---
 reactos/win32ss/user/ntuser/input.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/reactos/win32ss/user/ntuser/input.c b/reactos/win32ss/user/ntuser/input.c
index d4c2ed14981..a4201bb4652 100644
--- a/reactos/win32ss/user/ntuser/input.c
+++ b/reactos/win32ss/user/ntuser/input.c
@@ -429,6 +429,10 @@ UserAttachThreadInput(PTHREADINFO ptiFrom, PTHREADINFO ptiTo, BOOL fAttach)
             ptiFrom->rpdesk != ptiTo->rpdesk)
         return FALSE;
 
+    /* MSDN Note:
+       Keyboard and mouse events received by both threads are processed by the thread specifie
+     */
+
     /* If Attach set, allocate and link. */
     if (fAttach)
     {
@@ -475,6 +479,7 @@ UserAttachThreadInput(PTHREADINFO ptiFrom, PTHREADINFO ptiTo, BOOL fAttach)
         if (!pai) return FALSE;
 
         if (paiprev) paiprev->paiNext = pai->paiNext;
+        else if (!pai->paiNext) gpai = NULL;
 
         ExFreePoolWithTag(pai, USERTAG_ATTACHINFO);
         ERR("Attach Free! ptiFrom 0x%p  ptiTo 0x%p\n",ptiFrom,ptiTo);