Confirmed by multiple sources. http://www.reddit.com/r/programming/comments/erflu/i_know_you_guys_know_programming_but_if_someone/c1adu1j
If you do Alt-C it copies and you can paste with Ctrl-C (in a different program)
Alt-C = works, expected = Copy
Alt-X = works, expected = Cut
Alt-V = works, expected = Paste
Alt-Z = doesn't work, expected = Undo
Alt-Y = Doesn't work, expected = Undo
Alt-S = Doesn't work, expected = Save
We maintain our own clipboard. This is the root of the issue.
Copy-Paste also broken on OS X (at least on both Snow Leopard and Lion). Alt as substitute doesn't work.
Will this program ever support copy and paste?
Yeah, it's unfortunate. :/ Lots of work going into Shoes to fix this. But it's gonna take a while.