public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMargins);
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            if (Environment.OSVersion.Version.Major >= 6 && DwmIsCompositionEnabled())
            {
                // Get the current window handle
                IntPtr mainWindowPtr = new WindowInteropHelper(this).Handle;
                HwndSource mainWindowSrc = HwndSource.FromHwnd(mainWindowPtr);
                mainWindowSrc.CompositionTarget.BackgroundColor = Colors.Transparent;

                this.Background = Brushes.Transparent;

                // Set the proper margins for the extended glass part
                MARGINS margins = new MARGINS();
                margins.cxLeftWidth = -1;
                margins.cxRightWidth = -1;
                margins.cyTopHeight = -1;
                margins.cyBottomHeight = -1;

                int result = DwmExtendFrameIntoClientArea(mainWindowSrc.Handle, ref margins);

                if (result < 0)
                {
                    MessageBox.Show("An error occured while extending the glass unit.");
                }
            }
            addNewTab();
            //webBrowser1.LoadURL("http://google.co.uk");
        }