used to complete interactive tasks...

Dialog boxes are designed to reduce memory load and make
executing a task more user friendly since all information specific to
your current task is presented to you in one place, and they are easy
to navigate around using the Tab key or shortcut keys.
A dialog box generally presents you with a range of options to help
you to complete your task. You move around the dialog box using
the Tab key, and make changes to or selections from, these options
using special keys depending on the type of option. You can also
move to and change an option immediately using shortcut keys for
each option which makes it very quick to work in common dialog
boxes.
The various options in a dialog box are presented using combinations
of the 8 elements described in the following sections. Each element
represents a different type of option and is executed in a different
way. These 8 elements are: pushbuttons, checkboxes,
radiobuttons, editfields, listboxes, comboboxes, sliders and spinners.
Once you know how to navigate inside dialog boxes and how to
operate these 8 elements you should be able to work inside any
novel dialog box without any trouble.
Figure 18: The Find Dialog Box in a Word Processor
Here is a dialog box for finding a string of characters in the current
file. The dialog box appears on top of the file you are working on,
and becomes the active window (shown by the different coloured
title bar). There is an editfield in which you type, and there is a
checkbox for specifying whether it should match case or not, and a
group of two radiobuttons for specifying the direction of the search.
The pushbutton 'Find Next' is currently disabled since there is
nothing in the editfield to find yet, and it will be enabled when an
entry is made in the editfield. You can move the focus around the
dialog box using the Tab key. Each option has a shortcut key,
indicated by the underlined letter, and these are used with the Alt
key. The Query icon indicates that help on each option is available
in this dialog box, accessed by pressing F1 when the item you need
help on has the focus. End of Figure description.
Dialog boxes are simple windows which do not have a menu bar or a
Control Menu. There are two types of dialog box: the most common
is 'modal' which means that you cannot continue working in your
application until you close it - for example a Print dialog box requires
you either to execute the print command or to cancel the print
command before you can continue working.
The less common type of dialog box is 'modeless' which means that
you can continue working in your application while it is open. An
example of a modeless dialog box is the spell check dialog box in
Word 6.0. This allows you to swap between the spell check dialog
box and the document you are checking using the command Ctrl +
Tab. This command may also work for modeless dialog boxes in
other applications.
Dialog boxes usually contain an option called 'OK' which tells the
application to close the dialog box and execute everything you
specified in it. There is also usually an option called 'Cancel' which
closes the dialog box ignoring all the changes you may have made.
There may also be an option called 'Apply' which gives you the
chance to test changes you have made in the dialog box without
closing it. These are described in Section I 8 about Pushbuttons.
++ I 1: Message Boxes
Message boxes are simple dialog boxes which do not require much
dialog! They appear containing messages or warnings which usually
need to be acknowledged by choosing OK, in order to finish
executing a particular task you tried to perform, or to resolve a
particular problem before you can continue working - "disk not
inserted", for example. Other message or warning boxes could
appear if you have a printing problem, where the message might be
simply "there is no paper in the printer", and you can choose OK
after loading paper to continue printing, or choose Cancel to cancel
the Print command. Or, if you have asked to save a file with a name
that is already used by another document, you might be asked if you
wanted to Cancel the save operation, or to Replace the file.