Many thanks for that.
I followed your suggestion and copied the video over to your latest file.
I copied all the commands over from your VTS1 PGC1 to the new one and changed the command Id in the PGC Programs list.
It seemed to work except that the first button selected no video. Then I saw that in VTS1 PGC1 PreCommands, line 1 (for R2=1) was GoTo line 18. Maybe wrongly, I inserted a new line for R2=1 with a LinkProgram 1 and (as a guess) changed line 1 to look for R2=0.
I then had everything working when I did Test Export and viewed with
Nero. So next I did a full export and that worked OK with Nero. When I then burned it to DVD, and used it in my DVD machine, it started randomly failing to display the cyan line again, and always returned to Button 1 on going back to the menu.
Is this a problem with the DVD, or a problem with the DVD machine perhaps?