Unless I'm missing something, it seems the ability to copy/paste files in the browser was removed in Live 9. The only way I seem to be able to move files around is by dragging, which, depending on where I need to move the file to, can be kind of clunky.
On Live 8 I used to use the browser to preview samples and move them around when I was organizing my sample collection. A simple Ctrl-C/Ctrl-V was a lot faster than having to drag a sample to the correct folder and drop it in. Not really a huge deal, but it would be nice to have the copy/paste functionality back.