Apple iDVD '08 - Manual (Page 11)

Chapter 2 Learn iDVD 11
The Soft Frame theme, like many iDVD themes, defaults to the widescreen format
(16:9). To switch to standard format (4:3), choose Project > “Switch to Standard (4:3).”
Note: After you modify a menu, you can save it as a custom theme. A custom theme
appears in the Themes pane, listed below Favorites. You can use it for future projects,
just as you would any other theme.
Choose a set of themes
using this pop-up menu.
Click the disclosure
triangle to see all the
menu templates in the
theme family.