Layers V40 copied N times when re-arranging a single out of N overlapping layers. Layers V45 copies a constant number of times, twice: Current data to backing store, backing store to front layer, independent of N.
How do you do the re-arranging with only two copies if for example 3 or 4 smart refresh layers have their visible area changed after the single layer operation (moving, depth arrangement)? And the hidden area of a single smart refresh layers may consist of serveral cliprects = more than 1 backing store.
