The disappearing changes are occurring because of the process you are following.

You lose jumps most likely because you are not using the 'Links to List' feature. When you add a new disc and execute SNL, I bet you are prompted to delete your DVD List. Correct? And, you select Yes. When you do this, the previous DVD list is blown away along with any changes you might have made.

What you should be doing is under the 'Edit List' dialog, there's a section of the window entitled 'Links to List'. For Buttons added to the 'Links to List' area, upon SNL execution, a Jump action added to the end of the action list of each specified button that will cause a Jump to the first page of the SNL List.

My first clue that you did this wrong is the fact that you state all changes to the panels are being overwritten when you 'Add a New Disc' which usuallly involves an execution of the list generator in SNL.

I won't refer you to the SNL thread but I will refer you to the Jump Start documentation. If there's not enough stuff in there to get you going and help understand SNL, I don't have much free time right now but I'd be willing to offer support or specialized consultation services for a donation if needed.