Complex features that use dialog boxes will often hide options that are not commonly used from the main dialog, but make then accessible from a nested dialog.
For a button that displays a nested dialog box, append an ellipsis ( … ) to the end its label unless the nested dialog box is an alert box. Do not nest dialog boxes more than three deep. Four levels of nesting are reasonable if the fourth-level dialog boxes are only alert boxes. Because dialog boxes appear initially in the center of the screen, make the nested dialog boxes smaller than the main dialog box.