You can use initialization flags to modify the behavior and appearance of a common dialog box. Initialization flags are the values that you set in the Flags member of the structure used to create the dialog box. You use the flags to specify which controls in a dialog box receive initial values, to disable selected controls, and to modify the range of values the user can set with the controls. You also use the flags to enable hook procedures and custom templates for the dialog boxes.
For example, you set the CF_EFFECTS value in the Flags member of the CHOOSEFONT structure to direct the Font dialog box to display a set of controls. These controls let the user choose the color of the logical font as well as whether to use strikethrough and underline effects.
The initialization flag values are unique to each common dialog box and are described in detail with the structures that correspond to them.