Today I installed ReHIPS 2.4 stable build, and I created a few new isolated environments.
For all of them, I had "copy user data" selected.
But they didn't all copy the same data. My music player, MPC-BE, copied my Dropbox folder into the IE. But my FTP client, WinSCP, did not.
What's the difference? Both are installed in Program Files folder.
I have a third IE that I suspect that it copied Dropbox not right away, but later on. At least, I didn't notice it at first. Not sure on that one...
Here is a blogpost describing Copy User Data feature https://forum.rehips.com/index.php?topic=9560.0
Hopefully it'll cover all questions.