Window disappears returning from full screen

I added the following code to toggle full screen mode.

            Keyboard.KeyDown += delegate(object sender, KeyboardKeyEventArgs e)
            {
                if (e.Key == Key.Escape)
                    this.Exit();
 
                if (e.Key == Key.Enter)
                {
                    if (this.WindowState == WindowState.Fullscreen)
                        this.WindowState = WindowState.Normal;
                    else
                        this.WindowState = WindowState.Fullscreen;
                }
            };

Pressing enter once seems to make the window full screen. It does not seem to change the monitor resolution though (how would I do that?). However, pressing enter a second time to make the program display in a window again does not work. The console is left open, but the display window completely disappears. It does not even show up in the task bar any more. I pulled this code out of one of the examples included with the source code.