As far as I can remember, the Menu Title/Sub Chapter are always in MyDVD (never in Videowave). The Videowave is used to assemble and put together photos/videos/audio.
Unlike in the previous versions, it appears that you can no longer directly drop in a Videowave production (dmsm file) in MyDVD. I just started using the NXT 7 Pro yesterday and created a video file of my Videowave production (in Videowave menu ==> Output|Export As) . I then used that video file in MyDVD.
In the old version of MyDVD, it would allow you to use a Videowave production as an input file and even let you make edit to that Videowave production while in MyDVD. The other feature I miss in the current MyDVD is editing the Menu (changing menu title, chapter titles, editing background photo and audio) in one place.