Thanks,
Tried it, but it left, but it displays the rectangle from the last active window. Then as soon as you move your mouse, the last window reappears.
Show Desktop allows you to have a complete view of the desktop, without any window popping up. Also, if you have a lot of icons on your desktop that you want to use, as soon as the window opens they are hidden from view.
IMHO I prefer the Show Desktop and Switch between windows better