PrintWindow in .Net-applications in non-active desktop

I'm trying to make a window screenshot from a non-active desktop (created with CreateDesktop). I use the following code:

Code:

public partial class Form1 : Form
    {
        [DllImport("User32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool PrintWindow(IntPtr hwnd, IntPtr hDC, uint nFlags);

        public Form1()
        {
            InitializeComponent();
            timer1.Interval = 3000;
            timer1.Tick += new System.EventHandler(TimerProc);
            timer1.Start();
        }

        private void TimerProc(object sender, EventArgs e)
        {
            timer1.Stop();
            UsePrintWindow();
        }

        private void UsePrintWindow()
        {
            Graphics g = CreateGraphics();
            Bitmap bmp = new Bitmap(Size.Width, Size.Height, g);
            Graphics memoryGraphics = Graphics.FromImage(bmp);
            IntPtr dc = memoryGraphics.GetHdc();
            bool success = PrintWindow(Handle, dc, 0);
            memoryGraphics.ReleaseHdc(dc);
            bmp.Save("c:\\Test\\UsePrintWindow.bmp");
        }
    }

If I executed this code in non-active desktop on Win7 I receive the following picture:


If I executed this code in non-active desktop on Win2003 I receive the following picture:


Can anybody please advise how to fix it?

P.S. I created MFC-application with the same functionality.
It works fine on Win7 and Win2003.