The scenario is I have two items on a top layer (lets say the left and rights of a pair of earrings), and their accompannying shadows on a layer below. I'd like to be able to highlight both layers, draw a marquee around the right side earring (top layer) and shadow (bottom layer), and CDM+SHIFT+J them each to their own new layers, thus making four layers: left earring, left shadow, right earring, right shadow.
This doesn't currently work, but what is the quickest way to accomplish the same thing?
On a related note, one slow down to doing each layer at a time is that the command: CMD+SHIFT+D, to renew the last selection, only works sporadically for me (sometimes it simply doesn't renew any selection at all). What are the rules for when it should work and when it shouldn't?
A workaround to the unreloadable vanished selection is to first save the selection as an alpha channel (there's a little button to do that at bottom of Channels panel) from which the selection can be restored at any time by Cmd/Ctrl-clicking the channel's thumbnail.
I reported the problem of selections not being reloadable after cut or copy to new layer, but don't know whether it has been noted by Adobe. This thread might help get it fixed for the next update.