diff --git a/trunk/ProcessHacker.Native/Api/NativeDefinitions.cs b/trunk/ProcessHacker.Native/Api/NativeDefinitions.cs
index 8c1ba9b64..5f2dbff91 100644
--- a/trunk/ProcessHacker.Native/Api/NativeDefinitions.cs
+++ b/trunk/ProcessHacker.Native/Api/NativeDefinitions.cs
@@ -39,6 +39,7 @@ namespace ProcessHacker.Native.Api
         public const int GdiHandleBufferSize = 34;
 #endif
         public const int MaximumSupportedExtension = 512;
+        public const int MaximumWaitObjects = 64;
         public const int SecurityDescriptorMinLength = 20;
         public const int SecurityDescriptorRevision = 1;
         public static readonly int SecurityMaxSidSize =
diff --git a/trunk/ProcessHacker.Native/ProcessHacker.Native.csproj b/trunk/ProcessHacker.Native/ProcessHacker.Native.csproj
index 058deeb7a..1c5cb68e9 100644
--- a/trunk/ProcessHacker.Native/ProcessHacker.Native.csproj
+++ b/trunk/ProcessHacker.Native/ProcessHacker.Native.csproj
@@ -142,6 +142,7 @@
     <Compile Include="Threading\Semaphore.cs" />
     <Compile Include="Threading\SpinLock.cs" />
     <Compile Include="Threading\Timer.cs" />
+    <Compile Include="Threading\WaiterThread.cs" />
     <Compile Include="Ui\HandlePropertiesWindow.cs">
       <SubType>Form</SubType>
     </Compile>
diff --git a/trunk/ProcessHacker.Native/Security/ObjectSecurityInformation.cs b/trunk/ProcessHacker.Native/Security/ObjectSecurityInformation.cs
index 23fcc99a7..bb11c3f9e 100644
--- a/trunk/ProcessHacker.Native/Security/ObjectSecurityInformation.cs
+++ b/trunk/ProcessHacker.Native/Security/ObjectSecurityInformation.cs
@@ -74,6 +74,7 @@ namespace ProcessHacker.Native.Security
         private void ClearPool()
         {
             _pool.ForEach((alloc) => alloc.Dispose());
+            _pool.Clear();
         }
 
         #region ISecurityInformation Members
diff --git a/trunk/ProcessHacker.Native/Threading/WaiterThread.cs b/trunk/ProcessHacker.Native/Threading/WaiterThread.cs
new file mode 100644
index 000000000..0b86efa8b
--- /dev/null
+++ b/trunk/ProcessHacker.Native/Threading/WaiterThread.cs
@@ -0,0 +1,226 @@
+/*
+ * Process Hacker - 
+ *   waiter thread
+ * 
+ * Copyright (C) 2009 wj32
+ * 
+ * This file is part of Process Hacker.
+ * 
+ * Process Hacker is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Process Hacker is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Process Hacker.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading;
+using ProcessHacker.Native.Api;
+using ProcessHacker.Native.Objects;   
+using ProcessHacker.Native.Security;
+
+namespace ProcessHacker.Native.Threading
+{
+    public delegate void ObjectSignaledDelegate(ISynchronizable obj);
+
+    public class WaiterThread : IDisposable
+    {
+        private enum WaiterThreadMessageType
+        {
+            AddObject,
+            RemoveObject
+        }
+
+        private class WaiterThreadMessage
+        {
+            private WaiterThreadMessageType _type;
+            private object _param;
+
+            public WaiterThreadMessage(WaiterThreadMessageType type)
+                : this(type, null)
+            { }
+
+            public WaiterThreadMessage(WaiterThreadMessageType type, object param)
+            {
+                _type = type;
+                _param = param;
+            }
+
+            public WaiterThreadMessageType Type { get { return _type; } }
+            public object Param { get { return _param; } }
+        }
+
+        /// <summary>
+        /// Raised when an object is signaled.
+        /// </summary>
+        public event ObjectSignaledDelegate ObjectSignaled;
+
+        private bool _disposed = false;
+        private bool _terminating = false;
+        private object _disposeLock = new object();
+
+        private Thread _waiterThread;
+        private List<ISynchronizable> _waitObjects = new List<ISynchronizable>();
+
+        private Queue<WaiterThreadMessage> _waitMessageQueue = new Queue<WaiterThreadMessage>(); 
+        private Event _waitMessageEvent = new Event(true, false);
+
+        /// <summary>
+        /// Creates a waiter thread.
+        /// </summary>
+        public WaiterThread()
+        {
+            _waiterThread = new Thread(this.WaiterThreadStart);
+            _waiterThread.IsBackground = true;
+            _waiterThread.SetApartmentState(ApartmentState.STA);
+            _waiterThread.Start();
+        }
+
+        ~WaiterThread()
+        {
+            this.Dispose(false);
+        }
+
+        /// <summary>
+        /// Releases resources used by the waiter thread.
+        /// </summary>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        private void Dispose(bool disposing)
+        {
+            if (disposing)
+                Monitor.Enter(_disposeLock);
+
+            try
+            {
+                if (!_disposed)
+                {
+                    // Tell the waiter thread to terminate.
+                    _terminating = true;
+                    _waitMessageEvent.Set();
+
+                    _disposed = true;
+                }
+            }
+            finally
+            {
+                Monitor.Exit(_disposeLock);
+            }
+        }
+
+        /// <summary>
+        /// Adds an object for the waiter thread to wait on.
+        /// </summary>
+        /// <param name="obj">The object to wait for.</param>
+        public void Add(ISynchronizable obj)
+        {
+            lock (_waitMessageQueue)
+            {
+                if (_waitObjects.Count >= Win32.MaximumWaitObjects - 1)
+                    throw new TooManyWaitObjectsException();
+
+                this.SendWaiterThreadMessage(new WaiterThreadMessage(WaiterThreadMessageType.AddObject, obj));
+            }
+        }
+
+        private void OnObjectSignaled(ISynchronizable obj)
+        {
+            if (ObjectSignaled != null)
+                ObjectSignaled(obj);
+        }
+
+        /// <summary>
+        /// Removes an object the waiter thread is waiting on.
+        /// </summary>
+        /// <param name="obj">An object which is currently being waited on.</param>
+        public void Remove(ISynchronizable obj)
+        {
+            this.SendWaiterThreadMessage(new WaiterThreadMessage(WaiterThreadMessageType.RemoveObject, obj));
+        }
+
+        private void SendWaiterThreadMessage(WaiterThreadMessage message)
+        {
+            lock (_waitMessageQueue)
+            {
+                _waitMessageQueue.Enqueue(message);
+                _waitMessageEvent.Set();
+            }
+        }
+
+        private void WaiterThreadStart()
+        {
+            ISynchronizable[] waitObjects;
+
+            while (!_terminating)
+            {
+                waitObjects = new ISynchronizable[_waitObjects.Count + 1];
+                waitObjects[0] = _waitMessageEvent.Handle;
+                Array.Copy(_waitObjects.ToArray(), 0, waitObjects, 1, _waitObjects.Count);
+
+                NtStatus waitStatus = NativeHandle.WaitAny(waitObjects);
+
+                if (waitStatus == NtStatus.Wait0)
+                {
+                    // We have a message in the message queue (or we are terminating).
+                    WaiterThreadMessage message;
+
+                    // Lock and retrieve the message.
+                    lock (_waitMessageQueue)
+                    {
+                        if (_waitMessageQueue.Count > 0)
+                            message = _waitMessageQueue.Dequeue();
+                        else
+                            continue;
+                    }
+
+                    switch (message.Type)
+                    {
+                        case WaiterThreadMessageType.AddObject:
+                            {
+                                _waitObjects.Add((ISynchronizable)message.Param);
+                            }
+                            break;
+                        case WaiterThreadMessageType.RemoveObject:
+                            {
+                                _waitObjects.Remove((ISynchronizable)message.Param);
+                            }
+                            break;
+                    }
+                }
+                else if (waitStatus > NtStatus.Wait0 && waitStatus <= NtStatus.Wait63)
+                {
+                    // One of the objects was signaled.
+                    ISynchronizable signaledObject = waitObjects[(int)(waitStatus - NtStatus.Wait0)];
+                    // Remove the object now that it is signaled.
+                    _waitObjects.Remove(signaledObject);
+                    // Call the object-signaled event.
+                    OnObjectSignaled(signaledObject);
+                }
+            }
+        }
+    }
+
+    public class TooManyWaitObjectsException : Exception
+    {
+        public override string Message
+        {
+            get
+            {
+                return "An attempt was made to add too many objects to the wait list.";
+            }
+        }
+    }
+}