It sounds like a good idea avim1968, not sure how it could be implimented, but I do like it How about also the option to right click a layer and have the ability to save that layer only?
I also like your sugestion of having the "are you sure" option when deleting layers, sometimes when I am not concentrating enough I will delete what I think is now an obsolete "alpha mask" or something only to find that I really needed that layer, but I have since "done" another edit thus losing the undo deleted layer.
Good ideas.