I really like the ability to move files with drag'n'drop. I'd really like to have an option to copy too. My suggestion would be to press the control key for copying, as is the standard in Windows.
are u talking about remotely on a FTPD, or locally?
Locally = already support
FTPD = doesn't support copy (nothing to do with ffxp), the only way u will be able to copy is by using fxp, thats the closes way your going to copy