The options on the Control Panel Settings tab control which of the Control Panel Plugins are considered "favourites", such that they can be selected with one click on one of the 8 shortcut buttons in the main window.

In this tab, you place a tick against the plugins that you want to appear as a favourite. If you tick fewer than 8, there will be less than the full 8 one-click plugin buttons. If you tick more than 8, only the first 8 plugins selected will appear as a favourite.