From my point of view and workflow, a collaboration of two different remote folders are also needed.
In that case, it is easier for me to have two independent browsing windows of the remote server so that can make this work easier, than browsing back and forth again and again.
"Duplicate session" is what I currently use, but it would be easier if the windows were open and obvious on the same session, and drag and drop work as expected in this case too.
A close example to this, is the "Clone to Other View" feature of Notepad++ (where you can see different lines of the same code).