Copy file(s) from one project to another?

This seems trivial, but the obvious way to do it doesn't seem to work (right-click, copy and then switch to other project window and paste).

I simply want to copy source files from one project to another project without having to go to the file system. Is this possible?

Seeing this, maybe it isn't?
http://www.jetbrains.net/jira/browse/IDEABKL-2010

IDEA 5.1.2 (also on 5.1.1 and 5.1, I believe)
OS X 10.4.7