In 'Restore Saved Scene', when is 'add & restore' important to do?

After loading the SPL Brain Atlas, when I click on ‘Restore or delete saved scene views’, and then click on Restore a named scene, I get an error/warning message about ‘add & restore’, and I wonder:

  1. what it means, and
  2. in what circumstances would it be important to pay attention to it?
  3. what exactly will be permanently lost if I don’t select ‘add & restore’?
  4. should I just always ‘add & restore’?
  5. and what would ‘add & restore’ accomplish?

The error/warning reads,
“Data missing from Scene View”, and its window contains the messages,

“Add data to scene view “Brainstem” before restoring?
Data is present in the current scene but not in the scene view.
If you don’t add and restore, data not already saved to disk, or saved in another scene view, will be permanently lost!”

This was a warning we added when we realised that Scene Views were being used in a way not considered in the original design of different visualisations of the loaded data (for example hiding and showing different anatomical models in an atlas).
If new models were created from the loaded volumes after a scene view was already created, and then that scene view is restored, the new model could be lost unless it was already saved to disk from memory.

I would recommend always selecting ‘add & restore’ and then re-saving the atlas.