Before you all pile in asking for this I thought I’d save you the time. 
The MOST requested feature of any editor I’ve ever worked on.
You’ll be pleased to know that the foundations of this are in place, but it requires finding the time to spend a couple of days on that final step: paste (the biggest/hardest part).
Add/tag/like/comment on this topic to vote for it.
Sam
P.S. At least Undo was built into the editor from the start.
Along with Copy/Paste, Duplicate would be immensely useful too.
Yes. That would come along with the rest of the ‘bulk operations’; cut, copy, paste, duplicate. Its partially implemented already to support delete and cut and copy actually work now (to clipboard as xml), just the final step of importing from clipboard and pasting which is the most tricky one to implement. I expect to get this implemented during the beta, before release.
Ooh, this has been implemented. Moving to archive.