i set the number of links on my scene selection menu one shy. how do i go back and expand the number of links without creating a new scene selection menu?
The scene selection menus in DVD Architect are not "live" -- they don't update if you change the underlying chapters. Think of it as a "photograph" that you took when you inserted the menu. Adding something new to the scene doesn't change the photograph you already have.
To add the new button, go to the scene selection and copy / paste one of the other buttons. Then select the new button and edit its Button Properties to link to the appropriate chapter (on the Action tab).