Check box & Twist & Scroll bar 6.6.4. Drop-down menu: Drop-down menus allow designers to cluster navigation, functionality, or content together without having to display it all at once. Drop-down menus can be displayed by rolling over them, or they can be opened with a click. They can retract after a selection has been made or the cursor rolls off them, though not necessarily. Figure (17-1)(4) 6.6.5. Multiple-selection list (or list box): Multiple-selection lists enable users to select multiple items in a list. Figure (17-2)