You can also choose how the curtain behaves: as a normal window (so it can sit in front of, between, or behind other windows), as a desktop cover (so it covers everything on your desktop but stays behind windows), or as a traditional desktop background (so you continue to see all windows and anything on your desktop). You can also choose how the curtain interacts with OS X's Expose featu It can act as a standard window that embraces Expose's various preview states; remain in place, so Expose previews float over it; or hide completely when you activate Expose. An Automatic option attempts to choose the ideal Expose behavior, taking into account your Curtain Level settings.