I have a MyDVD (menu) project with 4 movies and a 'Play All' button.
The main menu default button is 'Play All' & play 'all movies on menu'.
Three of the movies have chapters.
Everything seems to work as expected when I Preview it.
When I burn the project to an image file, and play it, the first item highlighted is the first movie button (not the Play All button).
If I select 'Play All', all of the movies do not start at the beggining, but start at some chapter position.