Apple 2 manual 18Each checkbox can be on or off

C H A P T E R 3

Controls

Figure 3-18Each checkbox can be on or off

Checkbox off

Checkbox on

You can have one checkbox or as many as you need. Checkboxes are indepen- dent of one another, even when they offer related options. Any number of checkboxes can be on or off at the same time. It’s a good idea to group sets of checkboxes that are related, and to separate the groups from other groups of checkboxes and radio buttons. Each group may have a heading to identify it.

Labeling a checkbox unambiguously can be difficult. The label should imply two clearly opposite states. For example, the Sound preferences slip (Figure 3-18) shows a checkbox labeled “Action sound effects” that controls whether or not sound effects are played for actions. If the checkbox is selected, the action sound effects are played. The clearly opposite state, when the checkbox is not selected, is to not play action sound effects.

Checkboxes are usually capitalized like sentences. However, in some contexts it makes more sense to capitalize them like book titles. Checkbox labels should be all lowercase (except for proper nouns) if the checkboxes are part of a group and each label completes a sentence begun by the label of the group.

If you can’t think of a label for a checkbox that clearly implies its opposite state, you might be better off using radio buttons. With radio buttons, you can use two labels, thereby clarifying the states. It’s sometimes tempting to use a checkbox because one item takes up less space than two. However, the resulting item may be ambiguous and thus difficult to understand.

Sometimes using one checkbox instead of two radio buttons can make users focus more carefully on a choice between two states. One state is clearly labeled, but a user must think to figure out the unlabeled state. While thinking,

Checkboxes 3-19