DVD FAB Platinum using "Main Movie"

I can back up Blu-Ray disks easily and sweetly using the “full disk” option but when I select “main movie” my source disappears and I cannot select my drive. Should I be selecting a subdirectory on the disk?

Also could someone clarify the structure of Blu-Ray disks? It is not the simple audio ts and video ts of DVDs!!

For instance see the attached image (why can’t I just insert the image in this post?)

edit: I see it displays anyway so no problem!!

Any help gratefully appreciated

In fact, while “full disc” always works, any other option just loses the source but as soon as I reselect “full disc” it automatically opens the source!

Am I doing something wrong?

Should I be selecting a sub directory on the disc?