The top part of the group contains two tabs with identical options. The Main tab affects the behavior of the standard task switcher keys, and the Alternative tab controls the alternative keys. In the List windows dropdown list you specify whether you want to walk through the windows in all your virtual desktops or only those in the current desktop, and also whether you want windows to appear in the natural order or grouped. In Sort order you can affect the order in which you walk through windows. If you check Include desktop then the desktop itself will be listed among the windows, so that you can bring the desktop forward using the task switcher. The bottom half of this tab affects the appearance of the task switcher. Some of the effects have further options that you reach clicking the button to the right of the dropdown list.
button to the right of the dropdown list.