Actually, anything you do in DVD Studio Pro in a DVD-video project is part of the DVD spec, or rather, it's translated into it. If it's out of spec, then it's a bug in the way DVD SP builds it. It just happens that it brings a complexity to the way things that are stored, that it may cause significant navigation delays or worse.
The workaround is designing a series of twin menus with all buttons but one set to automatic activation. So, each time you select a button, you are actually replacing the menu with an identical menu but with the visual attributes you want to enable for that button. This is the reason why music can't be "continuous": it will play from the beginning each time you jump from button to button. This same trick is used to have animated buttons, etc.
Adolfo Rozenfeld
Buenos Aires - Argentina
www.adolforozenfeld.com