List boxes display a list of choices from which the user can select. A list box should be wide enough to display the longest line of text that it will contain. If the list of choices is longer than can be displayed, the list can be scrolled. When a list box is active, the user scrolls through it with the arrow keys or mouse. For a single- selection list box, the arrow keys or mouse are used to change the current selection. For a multiple-selection list box, the space bar or left mouse button is used to select or deselect one or more lines.