In Masking, add the capability to flatten a complex mask.
Create a Mask, make several Adds, maybe a few Subtractions, what the heck an Intersection, Now I want to simplify that from a bunch of components into one, I have no fear of wanting to undo this. Flatten the combined mask into one.
I create a subject mask, I make additions, I want to invert but I am too lazy to start over, Flatten the mask into one, now it will invert properly. the whole mask, not just one component (yes, creating the initial subject mask, then inverting, then adding etc would be better, but...)
By the way, could this save some memory, some hard drive space?