You can create an autoplay movie or slideshow, which is one that plays automatically when you insert it into a DVD player (it starts playing before the main menu appears).
If you create an autoplay movie or slideshow in iDVD and then preview the project, iDVD can unexpectedly quit after you close the preview window and return to the project. This occurs when you choose Undo from the Edit menu.
To resolve this issue, update to iDVD 6.0.4 or later.