For more information about guidelines for selecting access keys, see Chapter 4, "Input Basics."
With the mouse and pen, navigation to a particular field or control involves the user pointing to the field and clicking or tapping it. For button controls, this action also activates that button. For example, for check boxes, it toggles the check box setting and for command buttons, it carries out the command associated with that button.
The keyboard interface for navigation in secondary windows uses the TAB and SHIFT+TAB keys to move between controls, to the next and previous control, respectively. Each control has a property that determines its place in the navigation order. Set this property such that the user can move through the secondary window following the usual conventions for reading: in western countries, left-to-right and top-to-bottom, with the primary control the user interacts with located in the upper left area of the window. Order controls such that the user can progress through the window in a logical sequence, proceeding through groups of related controls. Command buttons for handling overall window transactions are usually at the end of the order sequence.
You need not provide TAB key access to every control in the window. When using static text as a label, set the control you associated with it as the appropriate navigational destination, not the static text field itself. In addition, combination controls such as combo boxes, drop-down combo boxes, and spin boxes are considered single controls for navigational purposes. Because option buttons typically appear as a group, use the TAB key for moving the input focus to the current set choice in that group, but not between individual options — use arrow keys for this purpose. For a group of check boxes, provide TAB navigation to each control because their settings are independent of each other.
Optionally, you can also use arrow keys to support keyboard navigation between controls in addition to the TAB navigation technique wherever the interface does not require those keys. For example, you can use the UP ARROW and DOWN ARROW keys to navigate between single-line text boxes or within a group of check boxes or command buttons. Always use arrow keys to navigate between option button choices and within list box controls.
You can also use access keys to provide navigation to controls within a secondary window. This allows the user to access a control by pressing and holding the ALT key and an alphanumeric key that matches the access key character designated in the label of the control.
Note
For more information about guidelines for selecting access keys, see Chapter 4, "Input Basics."
Unmodified alphanumeric keys also support navigation if the control that currently has the input focus does not use these keys for input. For example, if the input focus is currently on a check box control and the user presses an alphanumeric key, the input focus moves to the control with the matching access key. However, if the input focus is in a text box or list box, an alphanumeric key is used as text input for that control so the user cannot use it for navigation within the window without modifying it with the ALT key.
Access keys not only allow the user to navigate to the matching control, they have the same effect as clicking the control with the mouse. For example, pressing the access key for a command button carries out the action associated with that button. To ensure the user direct access to all controls, select unique access keys within a secondary window.
You can also use access keys to support navigation to a control, but then return the input focus to the control from which the user navigated. For example, when the user presses the access key for a specific command button that modifies the content of a list box, you can return the input focus to the list box after the command has been carried out.
OK and Cancel command buttons are typically not assigned access keys if they are the primary transaction keys for a secondary window. In this case, the ENTER and ESC keys, respectively, provide access to these buttons.
Pressing ENTER always navigates to the default command button, if one exists, and invokes the action associated with that button. If there is no current default command button, then a control can use the ENTER key for its own use.