Under the guidelines provided by CUA'91, a dialog box is known as an action window. Since this chapter discusses CUA guidelines, this term will be used herein when referring to the provisions made by CUA. The term "dialog box" will be used when referring to the implementation of these concepts under Presentation Manager.
Action windows used by an application may be either modal or modeless, although modeless windows are preferred under CUA. Both types of action window are defined as optimized windows; that is, they are created at a predefined optimal size for their function, and may not be resized by the user. However, the use of each type of action window is different, as explained below.
A dialog box is typically created using the Dialog Box Editor application supplied as part of the IBM Developer's Toolkit for OS/2 2.0, and is defined in a dialog template which is stored in a .DLG file and referenced from the application's resource script file. Dialog templates are fully described in the IBM OS/2 Version 2.0 Application Design Guide.
It is recommended that wherever possible, action windows should be created with a title bar. Since action windows typically appear as the result of a menu bar item being selected, the title bar should contain the name of the parent object, plus the same text as the menu bar item. This provides the user with a visual indication of the action which led to the action window being displayed.
As already mentioned, an action window should not be sizable by the user, although it may be movable. Similarly, a modal action window should not include minimize or maximize icons, since the user must complete the interaction with the action window at its optimal size prior to continuing with execution. In the case of a modeless action window, there is no point in providing a maximize icon since the window is created at an optimal size for the information it will contain. However, since a user may wish to suspend the dialog in order to interact with other windows, the user may wish to remove the action window from the desktop. In such cases, a modeless action window should include a minimize icon.