You can use the icon box to move quickly to another window without having to find its symbolic window in the panner.
The icon box can hold more icons than it can display at any one time. You can use the scroll bars to see these other icons.
The icon box shows an icon for each application that you have started. If you iconify a window, its icon in the icon box has a raised appearance.
You can display icons using their label, just their image, or both of these.