diff --git a/MTApiService/ICommandManager.cs b/MTApiService/ICommandManager.cs
index 2db3b80b..54514467 100755
--- a/MTApiService/ICommandManager.cs
+++ b/MTApiService/ICommandManager.cs
@@ -1,8 +1,7 @@
 namespace MTApiService
 {
-    public interface ICommandManager
+    internal interface ICommandManager
     {
-        void EnqueueCommandTask(MtCommandTask task);
-        MtCommandTask DequeueCommandTask();
+        MtCommandTask SendCommand(MtCommand task);
     }
 }
diff --git a/MTApiService/ITaskExecutor.cs b/MTApiService/ITaskExecutor.cs
new file mode 100644
index 00000000..c688c686
--- /dev/null
+++ b/MTApiService/ITaskExecutor.cs
@@ -0,0 +1,9 @@
+namespace MTApiService
+{
+    internal interface ITaskExecutor
+    {
+        void Execute(MtCommandTask task);
+        
+        int Handle { get; }
+    }
+}
diff --git a/MTApiService/MTApiService.csproj b/MTApiService/MTApiService.csproj
index 9bd012c7..56010ac1 100755
--- a/MTApiService/MTApiService.csproj
+++ b/MTApiService/MTApiService.csproj
@@ -62,6 +62,7 @@
   <ItemGroup>
     <Compile Include="ICommandManager.cs" />
     <Compile Include="IMetaTraderHandler.cs" />
+    <Compile Include="ITaskExecutor.cs" />
     <Compile Include="LogConfigurator.cs" />
     <Compile Include="MtCommandEventArgs.cs" />
     <Compile Include="IDisposableChannel.cs" />
diff --git a/MTApiService/MtApiProxy.cs b/MTApiService/MtApiProxy.cs
index f9307ab2..b29a32f8 100755
--- a/MTApiService/MtApiProxy.cs
+++ b/MTApiService/MtApiProxy.cs
@@ -11,13 +11,13 @@ namespace MTApiService
             : base(callbackContext, binding, remoteAddress)
         {
             InnerDuplexChannel.Faulted += InnerDuplexChannel_Faulted;
-            InnerDuplexChannel.Open();
         }
 
         #region IMtApi Members
 
         public bool Connect()
         {
+            InnerDuplexChannel.Open();
             return Channel.Connect();
         }
 
diff --git a/MTApiService/MtClient.cs b/MTApiService/MtClient.cs
index 81d7009c..68164915 100755
--- a/MTApiService/MtClient.cs
+++ b/MTApiService/MtClient.cs
@@ -6,8 +6,8 @@ using log4net;
 
 namespace MTApiService
 {
-    [CallbackBehavior(UseSynchronizationContext = false)]
-    public class MtClient: IMtApiCallback, IDisposable
+    [CallbackBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, UseSynchronizationContext = false)]
+    public class MtClient : IMtApiCallback, IDisposable
     {
         private const string ServiceName = "MtApiService";
 
@@ -17,28 +17,22 @@ namespace MTApiService
         #region Fields
         private static readonly ILog Log = LogManager.GetLogger(typeof(MtClient));
 
-        private MtApiProxy _proxy;
-        private bool _isConnected;
+        private readonly MtApiProxy _proxy;
         #endregion
 
-        #region Public Methods
-        public void Open(string host, int port)
+        #region ctor
+        public MtClient(string host, int port)
         {
-            Log.DebugFormat("Open: begin. host = {0}, port = {1}", host, port);
-
             if (string.IsNullOrEmpty(host))
                 throw new ArgumentNullException(nameof(host), "host is null or empty");
 
             if (port < 0 || port > 65536)
                 throw new ArgumentOutOfRangeException(nameof(port), "port value is invalid");
 
-            var urlService = $"net.tcp://{host}:{port}/{ServiceName}";
+            Host = host;
+            Port = port;
 
-            if (_proxy != null)
-            {
-                Log.Warn("Open: end. _proxy is not null.");
-                return;
-            }
+            var urlService = $"net.tcp://{host}:{port}/{ServiceName}";
 
             var bind = new NetTcpBinding(SecurityMode.None)
             {
@@ -56,28 +50,19 @@ namespace MTApiService
                     MaxNameTableCharCount = 2147483647
                 }
             };
-            // Commented next statement since it is not required
 
             _proxy = new MtApiProxy(new InstanceContext(this), bind, new EndpointAddress(urlService));
             _proxy.Faulted += ProxyFaulted;
-
-            Log.Debug("Open: end.");
         }
 
-        public void Open(int port)
+        public MtClient(int port)
         {
-            Log.DebugFormat("Open: begin. port = {0}", port);
-
             if (port < 0 || port > 65536)
                 throw new ArgumentOutOfRangeException(nameof(port), "port value is invalid");
 
-            var urlService = $"net.pipe://localhost/{ServiceName}_{port}";
+            Port = port;
 
-            if (_proxy != null)
-            {
-                Log.Warn("Open: end. _proxy is not null.");
-                return;
-            }
+            var urlService = $"net.pipe://localhost/{ServiceName}_{port}";
 
             var bind = new NetNamedPipeBinding(NetNamedPipeSecurityMode.None)
             {
@@ -95,61 +80,40 @@ namespace MTApiService
                     MaxNameTableCharCount = 2147483647
                 }
             };
-            // Commented next statement since it is not required
 
             _proxy = new MtApiProxy(new InstanceContext(this), bind, new EndpointAddress(urlService));
             _proxy.Faulted += ProxyFaulted;
-
-            Log.Debug("Open: end.");
         }
 
-        public void Close()
-        {
-            Log.Debug("Close: begin.");
 
-            if (_proxy != null)
-            {
-                _proxy.Faulted -= ProxyFaulted;
-                _proxy.Dispose();
-                _proxy = null;
-            }
-
-            _isConnected = false;
-
-            Log.Debug("Close: end.");
-        }
+        #endregion
 
+        #region Public Methods
         /// <exception cref="CommunicationException">Thrown when connection failed</exception>
         public void Connect()
         {
             Log.Debug("Connect: begin.");
 
-            if (_proxy == null)
+            if (_proxy.State != CommunicationState.Created)
             {
-                Log.Error("Connect: _proxy is not defined.");
-                throw new CommunicationException("Connection failed to service. Proxy is not defined (needs to call Open)");
-            }
-
-            if (_isConnected)
-            {
-                Log.Warn("Connected: end. Client is already connected.");
+                Log.ErrorFormat("Connected: end. Client has invalid state {0}", _proxy.State);
                 return;
             }
 
+            var coonected = false;
+
             try
             {
-                _isConnected = _proxy.Connect();
+                coonected = _proxy.Connect();
             }
             catch (Exception ex)
             {
                 Log.ErrorFormat("Connect: Exception - {0}", ex.Message);
 
-                Close();
-
                 throw new CommunicationException($"Connection failed to service. {ex.Message}");
             }
 
-            if (_isConnected == false)
+            if (coonected == false)
             {
                 Log.Error("Connect: end. Connection failed.");
                 throw new CommunicationException("Connection failed");
@@ -164,15 +128,11 @@ namespace MTApiService
 
             try
             {
-                _isConnected = false;
-
-                _proxy?.Disconnect();
+                _proxy.Disconnect();
             }
             catch (Exception ex)
             {
                 Log.ErrorFormat("Disconnect: Exception - {0}", ex.Message);
-
-                Close();
             }
 
             Log.Debug("Disconnect: end.");
@@ -183,19 +143,13 @@ namespace MTApiService
         {
             Log.DebugFormat("SendCommand: begin. commandType = {0}, parameters count = {1}", commandType, parameters?.Count);
 
-            MtResponse result;
-
-            if (_isConnected == false)
+            if (IsConnected == false)
             {
                 Log.Error("SendCommand: Client is not connected.");
                 throw new CommunicationException("Client is not connected.");
             }
 
-            if (_proxy == null)
-            {
-                Log.Error("SendCommand: Proxy is not defined.");
-                throw new CommunicationException("Proxy is not defined.");
-            }
+            MtResponse result;
 
             try
             {
@@ -205,11 +159,11 @@ namespace MTApiService
             {
                 Log.ErrorFormat("SendCommand: Exception - {0}", ex.Message);
 
-                Close();
-
                 throw new CommunicationException("Service connection failed! " + ex.Message);
             }
 
+            Log.DebugFormat("SendCommand: end. result = {0}", result);
+
             return result;
         }
 
@@ -218,18 +172,12 @@ namespace MTApiService
         {
             Log.Debug("GetQuotes: begin.");
 
-            if (_isConnected == false)
+            if (IsConnected == false)
             {
                 Log.Warn("GetQuotes: end. Client is not connected.");
                 return null;
             }
 
-            if (_proxy == null)
-            {
-                Log.Warn("GetQuotes: end. _proxy is not defined.");
-                return null;
-            }
-
             List<MtQuote> result;
 
             try
@@ -240,8 +188,6 @@ namespace MTApiService
             {
                 Log.ErrorFormat("GetQuotes: Exception - {0}", ex.Message);
 
-                Close();
-
                 throw new CommunicationException($"Service connection failed! {ex.Message}");
             }
 
@@ -260,7 +206,7 @@ namespace MTApiService
 
             if (quote == null) return;
 
-            QuoteUpdated?.Invoke( quote);
+            QuoteUpdated?.Invoke(quote);
 
             Log.Debug("OnQuoteUpdate: end.");
         }
@@ -287,7 +233,6 @@ namespace MTApiService
         {
             Log.Debug("OnServerStopped: begin.");
 
-            Close();
             ServerDisconnected?.Invoke(this, EventArgs.Empty);
 
             Log.Debug("OnServerStopped: end.");
@@ -306,7 +251,16 @@ namespace MTApiService
         #endregion
 
         #region Properties
-        public bool IsConnected => _proxy.State == CommunicationState.Opened && _isConnected;
+        public string Host { get; private set; }
+        public int Port { get; private set; }
+
+        private bool IsConnected
+        {
+            get
+            {
+                return _proxy.State == CommunicationState.Opened;
+            }
+        }
 
         #endregion
 
@@ -316,7 +270,6 @@ namespace MTApiService
         {
             Log.Debug("ProxyFaulted: begin.");
 
-            Close();
             ServerFailed?.Invoke(this, EventArgs.Empty);
 
             Log.Debug("ProxyFaulted: end.");
@@ -330,7 +283,7 @@ namespace MTApiService
         {
             Log.Debug("Dispose: begin.");
 
-            Close();
+            _proxy.Dispose();
 
             Log.Debug("Dispose: end.");
         }
diff --git a/MTApiService/MtCommand.cs b/MTApiService/MtCommand.cs
index 0e10281d..856cefbc 100755
--- a/MTApiService/MtCommand.cs
+++ b/MTApiService/MtCommand.cs
@@ -13,10 +13,13 @@ namespace MTApiService
         }
 
         [DataMember]
-        public int CommandType { get; private set; }
+        public int CommandType { get; set; }
 
         [DataMember]
-        public ArrayList Parameters { get; private set; }
+        public ArrayList Parameters { get; set; }
+
+        [DataMember]
+        public int ExpertHandle { get; set; }
 
         public override string ToString()
         {
diff --git a/MTApiService/MtEvent.cs b/MTApiService/MtEvent.cs
index 594d5fa0..a3452060 100644
--- a/MTApiService/MtEvent.cs
+++ b/MTApiService/MtEvent.cs
@@ -20,14 +20,4 @@ namespace MTApiService
             return $"EventType = {EventType}; Payload = {Payload}; ExpertHandle = {ExpertHandle}";
         }
     }
-
-    public class MtEventArgs: EventArgs
-    {
-        public MtEventArgs(MtEvent e)
-        {
-            Event = e;
-        }
-
-        public MtEvent Event { get; private set; }
-    }
 }
diff --git a/MTApiService/MtExecutorManager.cs b/MTApiService/MtExecutorManager.cs
index 4b23c089..230418c1 100755
--- a/MTApiService/MtExecutorManager.cs
+++ b/MTApiService/MtExecutorManager.cs
@@ -4,14 +4,13 @@ using log4net;
 
 namespace MTApiService
 {
-    internal class MtCommandExecutorManager : ICommandManager
+    internal class MtExecutorManager : ICommandManager
     {
         #region Private Fields
-        private static readonly ILog Log = LogManager.GetLogger(typeof(MtCommandExecutorManager));
-
-        private readonly List<MtExpert> _commandExecutors = new List<MtExpert>();
-        private readonly Queue<MtCommandTask> _commandTasks = new Queue<MtCommandTask>();
+        private static readonly ILog Log = LogManager.GetLogger(typeof(MtExecutorManager));
 
+        private readonly List<ITaskExecutor> _executorList = new List<ITaskExecutor>();
+        private readonly Dictionary<int, ITaskExecutor> _executorMap = new Dictionary<int, ITaskExecutor>();
         private readonly object _locker = new object();
         #endregion
 
@@ -23,149 +22,94 @@ namespace MTApiService
 
             lock (_locker)
             {
-                _commandExecutors.Clear();
-                _commandTasks.Clear();
+                _executorList.Clear();
+                _executorMap.Clear();
             }
 
             Log.Debug("Stop: end.");
         }
 
-        public void AddCommandExecutor(MtExpert commandExecutor)
+        public void AddExecutor(ITaskExecutor executor)
         {
-            if (commandExecutor == null)
-                throw new ArgumentNullException(nameof(commandExecutor));
+            if (executor == null)
+                throw new ArgumentNullException(nameof(executor));
 
-            Log.DebugFormat("AddCommandExecutor: begin. commandExecutor = {0}", commandExecutor);
+            Log.DebugFormat("AddExecutor: begin. executor = {0}", executor);
 
-            var notify = false;
             lock (_locker)
             {
-                if (_commandExecutors.Contains(commandExecutor))
+                if (_executorList.Contains(executor))
                 {
-                    Log.Warn("AddCommandExecutor: end. Command executor already exist.");
+                    Log.Warn("AddExecutor: end. Executor already exist.");
                     return;
                 }
 
-                _commandExecutors.Add(commandExecutor);
-                if (_commandTasks.Count > 0)
-                {
-                    notify = true;
-                }
-            }
-
-            commandExecutor.CommandExecuted += CommandExecutor_CommandExecuted;
-            commandExecutor.CommandManager = this;
-
-            if (notify)
-            {
-                NotifyCommandReady();
+                _executorList.Add(executor);
+                _executorMap[executor.Handle] = executor;
             }
 
             Log.Debug("AddCommandExecutor: end.");
         }
 
-        public void RemoveCommandExecutor(MtExpert commandExecutor)
+        public void RemoveExecutor(ITaskExecutor executor)
         {
-            if (commandExecutor == null)
-                throw new ArgumentNullException(nameof(commandExecutor));
+            if (executor == null)
+                throw new ArgumentNullException(nameof(executor));
 
-            Log.DebugFormat("RemoveCommandExecutor: begin. commandExecutor = {0}", commandExecutor);
+            Log.DebugFormat("RemoveExecutor: begin. executor = {0}", executor);
 
-            var notify = false;
             lock (_locker)
             {
-                if (_commandExecutors.Contains(commandExecutor) == false)
+                if (_executorList.Contains(executor) == false)
                 {
-                    Log.Warn("RemoveCommandExecutor: end. Command executor is not exist in collection.");
+                    Log.Warn("RemoveExecutor: end. Executor is not exist in collection.");
                     return;
                 }
 
-                _commandExecutors.Remove(commandExecutor);
-                if (_commandTasks.Count > 0)
+                _executorList.Remove(executor);
+                _executorMap.Remove(executor.Handle);
+            }
+
+            Log.Debug("RemoveExecutor: end.");
+        }
+
+        public MtCommandTask SendCommand(MtCommand command)
+        {
+            if (command == null)
+                throw new ArgumentNullException(nameof(command));
+
+            var task = new MtCommandTask(command);
+
+            Log.DebugFormat("SendTask: begin. command = {0}", command);
+
+            ITaskExecutor executor = null;
+
+            lock (_locker)
+            {
+                if (_executorMap.ContainsKey(command.ExpertHandle))
                 {
-                    notify = true;
+                    executor = _executorMap[command.ExpertHandle];
+                }
+                else
+                {
+                    executor = _executorList.Count > 0 ? _executorList[0] : null;
                 }
             }
 
-            commandExecutor.CommandExecuted -= CommandExecutor_CommandExecuted;
-            commandExecutor.CommandManager = null;
-
-            if (notify)
+            if (executor == null)
             {
-                NotifyCommandReady();
+                Log.Error("SendTask: Executor is null!");
+            }
+            else
+            {
+                executor.Execute(task);
             }
 
-            Log.Debug("RemoveCommandExecutor: end.");
+            Log.Debug("SendTask: end.");
+
+            return task;
         }
 
-        public void EnqueueCommandTask(MtCommandTask task)
-        {
-            if (task == null)
-                throw new ArgumentNullException(nameof(task));
-
-            Log.DebugFormat("EnqueueCommandTask: begin. task = {0}", task);
-
-            lock (_locker)
-            {
-                _commandTasks.Enqueue(task);
-            }
-
-            NotifyCommandReady();
-
-            Log.Debug("EnqueueCommandTask: end.");
-        }
-
-        public MtCommandTask DequeueCommandTask()
-        {
-            Log.Debug("DequeueCommandTask: called.");
-
-            lock (_locker)
-            {
-                return _commandTasks.Count > 0 ? _commandTasks.Dequeue() : null;
-            }
-        }
-
-        #endregion
-
-        #region Private Methods
-        private void NotifyCommandReady()
-        {
-            Log.Debug("NotifyCommandReady: begin.");
-
-            var commandExecutors = new List<MtExpert>();
-            lock (_locker)
-            {
-                commandExecutors.AddRange(_commandExecutors);
-            }
-
-            foreach (var executor in commandExecutors)
-            {
-                executor.NotifyCommandReady();
-            }
-
-            Log.DebugFormat("NotifyCommandReady: end. Notified executor count = {0}", commandExecutors.Count);
-        }
-
-        private void CommandExecutor_CommandExecuted(object sender, EventArgs e)
-        {
-            Log.Debug("CommandExecutor_CommandExecuted: begin.");
-
-            var notify = false;
-            lock (_locker)
-            {
-                if (_commandTasks.Count > 0)
-                {
-                    notify = true;
-                }
-            }
-
-            if (notify)
-            {
-                NotifyCommandReady();
-            }
-
-            Log.Debug("CommandExecutor_CommandExecuted: end.");
-        }
         #endregion
     }
 }
diff --git a/MTApiService/MtExpert.cs b/MTApiService/MtExpert.cs
index a66dd517..0b90053e 100755
--- a/MTApiService/MtExpert.cs
+++ b/MTApiService/MtExpert.cs
@@ -1,9 +1,10 @@
 using System;
 using log4net;
+using System.Collections.Generic;
 
 namespace MTApiService
 {
-    public class MtExpert
+    internal class MtExpert: ITaskExecutor
     {
         public delegate void MtQuoteHandler(MtExpert expert, MtQuote quote);
         public delegate void MtEventHandler(MtExpert expert, MtEvent e);
@@ -12,8 +13,8 @@ namespace MTApiService
         private static readonly ILog Log = LogManager.GetLogger(typeof(MtExpert));
 
         private readonly IMetaTraderHandler _mtHadler;
-        private MtCommandTask _commandTask;
-        private ICommandManager _commandManager;
+        private MtCommandTask _currentTask;
+        private readonly Queue<MtCommandTask> _taskQueue = new Queue<MtCommandTask>();
         private readonly object _locker = new object();
         #endregion
 
@@ -42,9 +43,8 @@ namespace MTApiService
         {
             Log.DebugFormat("SendResponse: begin. response = {0}", response);
 
-            _commandTask.SetResult(response);
-            _commandTask = null;
-            FireOnCommandExecuted();
+            _currentTask.SetResult(response);
+            _currentTask = null;
 
             Log.Debug("SendResponse: end.");
         }
@@ -53,20 +53,16 @@ namespace MTApiService
         {
             Log.Debug("GetCommandType: called.");
 
-            var commandManager = CommandManager;
-            if (commandManager != null)
-            {
-                _commandTask = commandManager.DequeueCommandTask();
-            }
+            _currentTask = DequeueTask();
 
-            return _commandTask?.Command?.CommandType ?? 0;
+            return _currentTask?.Command?.CommandType ?? 0;
         }
 
         public object GetCommandParameter(int index)
         {
             Log.DebugFormat("GetCommandType: called. index = {0}", index);
 
-            var command = _commandTask?.Command;
+            var command = _currentTask?.Command;
             if (command?.Parameters != null && index >= 0 && index < command.Parameters.Count)
             {
                 return command.Parameters[index];
@@ -91,7 +87,22 @@ namespace MTApiService
 
         #endregion
 
+        #region ITaskExecutor
+
+        public void Execute(MtCommandTask task)
+        {
+            lock (_taskQueue)
+            {
+                _taskQueue.Enqueue(task);
+            }
+
+            NotifyCommandReady();
+        }
+
+        #endregion
+
         #region Properties
+
         private MtQuote _quote;
         public MtQuote Quote
         {
@@ -134,41 +145,34 @@ namespace MTApiService
             }
         }
 
-        public ICommandManager CommandManager
-        {
-            private get
-            {
-                lock (_locker)
-                {
-                    return _commandManager;
-                }
-            }
-            set
-            {
-                lock (_locker)
-                {
-                    _commandManager = value;
-                }
-            }
-        }
-
-        #endregion
-
-        #region IMtCommandExecutor
-        public void NotifyCommandReady()
-        {
-            Log.Debug("NotifyCommandReady: begin.");
-
-            SendTickToMetaTrader();
-
-            Log.Debug("NotifyCommandReady: end.");
-        }
         #endregion
 
         #region Private Methods
-        private void SendTickToMetaTrader()
+        private MtCommandTask DequeueTask()
         {
+            Log.Debug("DequeueTask: called.");
+
+            MtCommandTask task;
+            int count = 0;
+
+            lock (_locker)
+            {
+                count = _taskQueue.Count;
+                task = _taskQueue.Count > 0 ? _taskQueue.Dequeue() : null;
+            }
+
+            Log.DebugFormat("DequeueTask: end. left task count = {0}.", count);
+
+            return task;
+        }
+
+        private void NotifyCommandReady()
+        {
+            Log.Debug("NotifyCommandReady: begin.");
+
             _mtHadler.SendTickToMetaTrader(Handle);
+
+            Log.Debug("NotifyCommandReady: end.");
         }
 
         private void FireOnQuoteChanged(MtQuote quote)
@@ -181,11 +185,6 @@ namespace MTApiService
             Deinited?.Invoke(this, EventArgs.Empty);
         }
 
-        private void FireOnCommandExecuted()
-        {
-            CommandExecuted?.Invoke(this, EventArgs.Empty);
-        }
-
         private void FireOnMtEvent(MtEvent mtEvent)
         {
             OnMtEvent?.Invoke(this, mtEvent);
@@ -195,7 +194,6 @@ namespace MTApiService
         #region Events
         public event EventHandler Deinited;
         public event MtQuoteHandler QuoteChanged;
-        public event EventHandler CommandExecuted;
         public event MtEventHandler OnMtEvent;
         #endregion
     }
diff --git a/MTApiService/MtServer.cs b/MTApiService/MtServer.cs
index e133b741..ce39bec8 100755
--- a/MTApiService/MtServer.cs
+++ b/MTApiService/MtServer.cs
@@ -21,7 +21,7 @@ namespace MTApiService
 
         private readonly MtService _service;
         private readonly List<ServiceHost> _hosts = new List<ServiceHost>();
-        private readonly MtCommandExecutorManager _executorManager = new MtCommandExecutorManager();
+        private readonly MtExecutorManager _executorManager = new MtExecutorManager();
         private readonly List<MtExpert> _experts = new List<MtExpert>();
         #endregion
 
@@ -149,7 +149,7 @@ namespace MTApiService
                 _experts.Add(expert);
             }
 
-            _executorManager.AddCommandExecutor(expert);
+            _executorManager.AddExecutor(expert);
 
             _service.OnQuoteAdded(expert.Quote);
 
@@ -170,11 +170,20 @@ namespace MTApiService
                 return null;
             }
 
-            var task = new MtCommandTask(command);
-            _executorManager.EnqueueCommandTask(task);
+            var task = _executorManager.SendCommand(command);
 
             //wait for execute command in MetaTrader
-            var response = task.WaitResult(WaitResponseTime);
+            MtResponse response = null;
+            try
+            {
+                response = task.WaitResult(WaitResponseTime);
+            }
+            catch (Exception ex)
+            {
+                Log.WarnFormat("SendCommand: Exception - {0}", ex.Message);
+            }
+
+            Log.DebugFormat("SendCommand: end. response = {0}", response);
 
             return response;
         }
@@ -371,7 +380,7 @@ namespace MTApiService
                 expertsCount = _experts.Count;
             }
 
-            _executorManager.RemoveCommandExecutor(expert);
+            _executorManager.RemoveExecutor(expert);
 
             expert.Deinited -= expert_Deinited;
             expert.QuoteChanged -= expert_QuoteChanged;
diff --git a/MtApi/ExtensionMethods.cs b/MtApi/ExtensionMethods.cs
deleted file mode 100755
index 9871cb9e..00000000
--- a/MtApi/ExtensionMethods.cs
+++ /dev/null
@@ -1,37 +0,0 @@
-using System;
-using System.Threading.Tasks;
-
-namespace MtApi
-{
-    static class ExtensionMethods
-    {
-        #region Event Methods
-
-        public static Task FireEventAsync(this MtApiQuoteHandler evenHandler, object sender, string symbol, double bid, double ask)
-        {
-            return Task.Factory.StartNew(() =>
-            {
-                evenHandler?.Invoke(sender, symbol, bid, ask);
-            });
-        }
-
-        public static Task FireEventAsync(this EventHandler eventHandler, object sender)
-        {
-            return Task.Factory.StartNew(() =>
-            {
-                eventHandler?.Invoke(sender, EventArgs.Empty);
-            });
-        }
-
-        public static Task FireEventAsync<T>(this EventHandler<T> eventHandler, object sender, T e)
-            where T : EventArgs
-        {
-            return Task.Factory.StartNew(() =>
-            {
-                eventHandler?.Invoke(sender, e);
-            });
-        }
-
-        #endregion
-    }
-}
diff --git a/MtApi/MtApi.csproj b/MtApi/MtApi.csproj
index fb8ff55c..985c00c7 100755
--- a/MtApi/MtApi.csproj
+++ b/MtApi/MtApi.csproj
@@ -64,7 +64,6 @@
     <Compile Include="EnumSymbolInfoInteger.cs" />
     <Compile Include="EnumTerminalInfoDouble.cs" />
     <Compile Include="EnumTerminalInfoInteger.cs" />
-    <Compile Include="ExtensionMethods.cs" />
     <Compile Include="Monitors\AvailabilityOrdersEventArgs.cs" />
     <Compile Include="MqlRates.cs" />
     <Compile Include="MqlTick.cs" />
diff --git a/MtApi/MtApiClient.cs b/MtApi/MtApiClient.cs
index 65c4a8b2..977525db 100755
--- a/MtApi/MtApiClient.cs
+++ b/MtApi/MtApiClient.cs
@@ -8,6 +8,7 @@ using System.ServiceModel;
 using MtApi.Requests;
 using MtApi.Responses;
 using Newtonsoft.Json;
+using System.Threading.Tasks;
 
 namespace MtApi
 {
@@ -27,7 +28,7 @@ namespace MtApi
         #endregion
 
         #region Private Fields
-        private readonly MtClient _client = new MtClient();
+        private MtClient _client;
         private readonly object _locker = new object();
         private MtConnectionState _connectionState = MtConnectionState.Disconnected;
         #endregion
@@ -37,13 +38,6 @@ namespace MtApi
         public MtApiClient()
         {
             LogConfigurator.Setup(LogProfileName);
-
-            _client.QuoteAdded += _client_QuoteAdded;
-            _client.QuoteRemoved += _client_QuoteRemoved;
-            _client.QuoteUpdated += _client_QuoteUpdated;
-            _client.ServerDisconnected += _client_ServerDisconnected;
-            _client.ServerFailed += _client_ServerFailed;
-            _client.MtEventReceived += _client_MtEventReceived;
         }
         #endregion
 
@@ -55,8 +49,7 @@ namespace MtApi
         ///<param name="port">Port of host connection (default 8222) </param>
         public void BeginConnect(string host, int port)
         {
-            Action<string, int> connectAction = Connect;
-            connectAction.BeginInvoke(host, port, null, null);
+            Task.Factory.StartNew(() => Connect(host, port));
         }
 
         ///<summary>
@@ -65,8 +58,7 @@ namespace MtApi
         ///<param name="port">Port of host connection (default 8222) </param>
         public void BeginConnect(int port)
         {
-            Action<int> connectAction = Connect;
-            connectAction.BeginInvoke(port, null, null);
+            Task.Factory.StartNew(() => Connect(port));
         }
 
         ///<summary>
@@ -74,8 +66,7 @@ namespace MtApi
         ///</summary>
         public void BeginDisconnect()
         {
-            Action disconnectAction = Disconnect;
-            disconnectAction.BeginInvoke(null, null);
+            Task.Factory.StartNew(() => Disconnect(false));
         }
 
         ///<summary>
@@ -83,12 +74,7 @@ namespace MtApi
         ///</summary>
         public List<MtQuote> GetQuotes()
         {
-            IEnumerable<MTApiService.MtQuote> quotes;
-            lock (_client)
-            {
-                quotes = _client.GetQuotes();
-            }
-
+            var quotes = _client.GetQuotes();
             return quotes?.Select(q => new MtQuote(q)).ToList();
         }
         #endregion
@@ -1706,44 +1692,81 @@ namespace MtApi
         #endregion
 
         #region Private Methods
-        private void Connect(string host, int port)
+        private MtClient Client
         {
-            UpdateConnectionState(MtConnectionState.Connecting, $"Connecting to {host}:{port}");
-            try
+            get
             {
-                lock (_client)
+                lock(_locker)
                 {
-                    _client.Open(host, port);
-                    _client.Connect();
+                    return _client;
                 }
             }
-            catch (Exception e)
+        }
+
+        private void Connect(MtClient client)
+        {
+            lock (_locker)
             {
-                UpdateConnectionState(MtConnectionState.Failed, $"Failed connection to {host}:{port}. {e.Message}");
-                return;
+                if (_connectionState == MtConnectionState.Connected
+                    || _connectionState == MtConnectionState.Connecting)
+                {
+                    return;
+                }
+
+                _connectionState = MtConnectionState.Connecting;
             }
-            UpdateConnectionState(MtConnectionState.Connected, $"Connected  to  {host}:{port}");
-            OnConnected();
+
+            string message = string.IsNullOrEmpty(client.Host) ? $"Connecting to localhost:{client.Port}" : $"Connecting to {client.Host}:{client.Port}";
+            ConnectionStateChanged?.Invoke(this, new MtConnectionEventArgs(MtConnectionState.Connecting, message));
+
+            var state = MtConnectionState.Failed;
+
+            lock (_locker)
+            {
+                try
+                {
+                    client.Connect();
+                    state = MtConnectionState.Connected;
+                }
+                catch (Exception e)
+                {
+                    client.Dispose();
+                    message = string.IsNullOrEmpty(client.Host) ? $"Failed connection to localhost:{client.Port}. {e.Message}" : $"Failed connection to {client.Host}:{client.Port}. {e.Message}";
+                }
+
+                if (state == MtConnectionState.Connected)
+                {
+                    _client = client;
+                    _client.QuoteAdded += _client_QuoteAdded;
+                    _client.QuoteRemoved += _client_QuoteRemoved;
+                    _client.QuoteUpdated += _client_QuoteUpdated;
+                    _client.ServerDisconnected += _client_ServerDisconnected;
+                    _client.ServerFailed += _client_ServerFailed;
+                    _client.MtEventReceived += _client_MtEventReceived;
+                    message = string.IsNullOrEmpty(client.Host) ? $"Connected to localhost:{client.Port}" : $"Connected to  { client.Host}:{client.Port}";
+                }
+
+                _connectionState = state;
+            }
+
+            ConnectionStateChanged?.Invoke(this, new MtConnectionEventArgs(state, message));
+
+            if (state == MtConnectionState.Connected)
+            {
+                OnConnected();
+            }
+        }
+
+        private void Connect(string host, int port)
+        {
+            var client = new MtClient(host, port);
+            Connect(client);
         }
 
         private void Connect(int port)
         {
-            UpdateConnectionState(MtConnectionState.Connecting, $"Connecting to 'localhost':{port}");
-            try
-            {
-                lock (_client)
-                {
-                    _client.Open(port);
-                    _client.Connect();
-                }
-            }
-            catch (Exception e)
-            {
-                UpdateConnectionState(MtConnectionState.Failed, $"Failed connection  to 'localhost':{port}. {e.Message}");
-                return;
-            }
-            UpdateConnectionState(MtConnectionState.Connected, $"Connected to 'localhost':{port}");
-            OnConnected();
+            var client = new MtClient(port);
+            Connect(client);
         }
 
         private void OnConnected()
@@ -1755,50 +1778,67 @@ namespace MtApi
             }
         }
 
-        private void Disconnect()
+        private void Disconnect(bool failed)
         {
-            lock (_client)
-            {
-                _client.Disconnect();
-                _client.Close();
-            }
+            var state =  failed ? MtConnectionState.Disconnected : MtConnectionState.Disconnected;
+            var message = failed ? "Connection Failed" : "Disconnected";
 
-            UpdateConnectionState(MtConnectionState.Disconnected, "Disconnected");
-        }
-
-        private void UpdateConnectionState(MtConnectionState state, string message)
-        {
-            var changed = false;
             lock (_locker)
             {
-                if (_connectionState != state)
+                if (_connectionState == MtConnectionState.Disconnected
+                    || _connectionState == MtConnectionState.Failed)
+                    return;
+
+                if (_client != null)
                 {
-                    _connectionState = state;
-                    changed = true;
+                    _client.QuoteAdded -= _client_QuoteAdded;
+                    _client.QuoteRemoved -= _client_QuoteRemoved;
+                    _client.QuoteUpdated -= _client_QuoteUpdated;
+                    _client.ServerDisconnected -= _client_ServerDisconnected;
+                    _client.ServerFailed -= _client_ServerFailed;
+                    _client.MtEventReceived -= _client_MtEventReceived;
+
+                    if (!failed)
+                    {
+                        _client.Disconnect();
+                    }
+
+                    _client.Dispose();
+
+                    _client = null;
                 }
+
+                _connectionState = state;
             }
 
-            if (changed)
-            {
-                ConnectionStateChanged.FireEventAsync(this, new MtConnectionEventArgs(state, message));
-            }
+
+            ConnectionStateChanged?.Invoke(this, new MtConnectionEventArgs(state, message));
         }
 
         private T SendCommand<T>(MtCommandType commandType, ArrayList commandParameters)
         {
             MtResponse response;
+
+            var client = Client;
+            if (client == null)
+            {
+                throw new MtConnectionException("No connection");
+            }
+
             try
             {
-                lock (_client)
-                {
-                    response = _client.SendCommand((int)commandType, commandParameters);
-                }
+                response = client.SendCommand((int)commandType, commandParameters);
             }
             catch (CommunicationException ex)
             {
                 throw new MtConnectionException(ex.Message, ex);
             }
 
+            if (response == null)
+            {
+                throw new MtExecutionException(MtErrorCode.MtApiCustomError, "Response from MetaTrader is null");
+            }
+
             var responseValue = response.GetValue();
             return responseValue != null ? (T)responseValue : default(T);
         }
@@ -1815,25 +1855,14 @@ namespace MtApi
                             });
             var commandParameters = new ArrayList { serializer };
 
-            MtResponseString res;
-            try
-            {
-                lock (_client)
-                {
-                    res = (MtResponseString)_client.SendCommand((int)MtCommandType.MtRequest, commandParameters);
-                }
-            }
-            catch (CommunicationException ex)
-            {
-                throw new MtConnectionException(ex.Message, ex);
-            }
+            var res = SendCommand<string>(MtCommandType.MtRequest, commandParameters);
 
             if (res == null)
             {
                 throw new MtExecutionException(MtErrorCode.MtApiCustomError, "Response from MetaTrader is null");
             }
 
-            var response = JsonConvert.DeserializeObject<T>(res.Value);
+            var response = JsonConvert.DeserializeObject<T>(res);
             if (response.ErrorCode != 0)
             {
                 throw new MtExecutionException((MtErrorCode)response.ErrorCode, response.ErrorMessage);
@@ -1846,37 +1875,29 @@ namespace MtApi
         {
             if (quote != null)
             {
-                if (_isBacktestingMode)
-                {
-                    QuoteUpdate?.Invoke(this, new MtQuoteEventArgs(new MtQuote(quote)));
-                    QuoteUpdated?.Invoke(this, quote.Instrument, quote.Bid, quote.Ask);
-                }
-                else
-                {
-                    QuoteUpdate?.FireEventAsync(this, new MtQuoteEventArgs(new MtQuote(quote)));
-                    QuoteUpdated.FireEventAsync(this, quote.Instrument, quote.Bid, quote.Ask);
-                }
+                QuoteUpdate?.Invoke(this, new MtQuoteEventArgs(new MtQuote(quote)));
+                QuoteUpdated?.Invoke(this, quote.Instrument, quote.Bid, quote.Ask);
             }
         }
 
         private void _client_ServerDisconnected(object sender, EventArgs e)
         {
-            UpdateConnectionState(MtConnectionState.Disconnected, "MtApi is disconnected");
+            Disconnect(false);
         }
 
         private void _client_ServerFailed(object sender, EventArgs e)
         {
-            UpdateConnectionState(MtConnectionState.Failed, "Failed connection with MtApi");
+            Disconnect(true);
         }
 
         private void _client_QuoteRemoved(MTApiService.MtQuote quote)
         {
-            QuoteRemoved.FireEventAsync(this, new MtQuoteEventArgs(new MtQuote(quote)));
+            QuoteRemoved?.Invoke(this, new MtQuoteEventArgs(new MtQuote(quote)));
         }
 
         private void _client_QuoteAdded(MTApiService.MtQuote quote)
         {
-            QuoteAdded.FireEventAsync(this, new MtQuoteEventArgs(new MtQuote(quote)));
+            QuoteAdded?.Invoke(this, new MtQuoteEventArgs(new MtQuote(quote)));
         }
 
         private void _client_MtEventReceived(MtEvent e)
@@ -1897,7 +1918,7 @@ namespace MtApi
 
         private void FireOnLastTimeBar(MtTimeBar timeBar)
         {
-            OnLastTimeBar.FireEventAsync(this, new TimeBarArgs(timeBar));
+            OnLastTimeBar?.Invoke(this, new TimeBarArgs(timeBar));
         }
 
         private void BacktestingReady()
diff --git a/TestClients/TestApiClientUI/Form1.cs b/TestClients/TestApiClientUI/Form1.cs
index 2dea1035..bc919517 100644
--- a/TestClients/TestApiClientUI/Form1.cs
+++ b/TestClients/TestApiClientUI/Form1.cs
@@ -135,11 +135,27 @@ namespace TestApiClientUI
             PrintLog(msg);
         }
 
-        private void apiClient_QuoteUpdated(object sender, string symbol, double bid, double ask)
+        private void TestCallback(string symbol)
         {
-            Console.WriteLine(@"Quote: Symbol = {0}, Bid = {1}, Ask = {2}", symbol, bid, ask);
+            int bars = 0;
+            try
+            {
+                bars = _apiClient.iBars(symbol, ChartPeriod.PERIOD_M5);
+            }
+            catch(Exception ex)
+            {
+                Console.WriteLine("TestCallback:  Exception - {0}", ex.Message);
+            }
+
+            if (bars > 0)
+                Console.WriteLine("TestCallback:  iBar = {0}", bars);
         }
 
+        private void apiClient_QuoteUpdated(object sender, string symbol, double bid, double ask)
+        {
+            Console.WriteLine(@"Quote: Symbol = {0}, Bid = {1}, Ask = {2}", symbol, bid, ask);            
+            TestCallback(symbol);
+        }
 
         private void _apiClient_QuoteUpdate(object sender, MtQuoteEventArgs e)
         {
@@ -741,13 +757,13 @@ namespace TestApiClientUI
 
             Console.WriteLine($"Finished time: {DateTime.Now}");
 
-            using (var file = new System.IO.StreamWriter($@"{System.IO.Path.GetTempPath()}\MtApi\test.txt"))
-            {
-                foreach (var value in openPriceList)
-                {
-                    file.WriteLine(value);
-                }
-            }
+            //using (var file = new System.IO.StreamWriter($@"{System.IO.Path.GetTempPath()}\MtApi\test.txt"))
+            //{
+            //    foreach (var value in openPriceList)
+            //    {
+            //        file.WriteLine(value);
+            //    }
+            //}
         }
 
         private void button7_Click(object sender, EventArgs e)
diff --git a/mq4/MtApi.ex4 b/mq4/MtApi.ex4
index b70a001e..b32018c9 100755
Binary files a/mq4/MtApi.ex4 and b/mq4/MtApi.ex4 differ
diff --git a/mq4/MtApi.mq4 b/mq4/MtApi.mq4
index 5603cfa8..d1364806 100755
Binary files a/mq4/MtApi.mq4 and b/mq4/MtApi.mq4 differ