Missing WM_Messages on WPF

Question

I'm having problems to minimize/restore my wpf app by clicking on windows taskbar. Sometimes it works, sometimes it does not. So, I added a hook to app main window to try to see if events were coming or not. Sometimes they do, sometimes they do not. Then I use Spy++ to see if events were at least launched... Yes! They are. So why am I receiving just some of them?

public MyMainWindow()
{
    InitializeComponent();
    this.SourceInitialized += new EventHandler(OnSourceInitialized);
}

void OnSourceInitialized(object sender, EventArgs e)
{
    HwndSource source = (HwndSource)PresentationSource.FromVisual(this);
    source.AddHook(new HwndSourceHook(HandleMessages));
}

private IntPtr HandleMessages(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    switch (msg) {
        case  0x0112://WM_SYSCOMMAND:
            switch ((int)wParam & 0xFFF0) {
                case  0xF020://SC_MINIMIZE:
                    break;
                case  0xF120://SC_RESTORE:
                    break;
            }
            break;
    }
}

I have a custom main and I'm using Caliburn Micro with customized Bootstrapper.

---

I think I made a simplified case where this problem can be seen (not sure about this been same source of my problem). I used a Timer to emulate been waiting for async socket/activeX response. As is possible to see, clicking over taskbar, sometimes window will not be maximized/minimized.

Still don't know how to solve it.

using System;
using System.Threading;
using System.Windows;
using System.Windows.Threading;
using Timer = System.Timers.Timer;


namespace Garbage
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        var dispatcherTimer = new DispatcherTimer { Interval = new TimeSpan(0,0,0,0,10) };
        dispatcherTimer.Tick += (o, e) =>
                                    {
                                        var waintingForSocketAsyncRenponseEmulation = new Timer(10);

                                        waintingForSocketAsyncRenponseEmulation.Elapsed += delegate
                                                            {
                                                                lock (this)
                                                                {
                                                                    Monitor.Pulse(this);
                                                                }
                                                            };

                                        waintingForSocketAsyncRenponseEmulation.Start();

                                        lock (this)
                                        {
                                            Monitor.Wait(this);
                                        }
                                    };
        dispatcherTimer.Start();
    }
}

}