Okay, I found them. Thanks.
Yes, please update the handbook.
Dragging files into PowerTools for the purpose of working with them in File Tools is a rather unconventional technique. Usually, dragging files means that you are moving or copying them.
As an alternative, I suggest that you provide File Tools as a top-level tool within PowerTools, and then (within File Tools) provide a standard file- and folder-selection dialog to populate the file list.
Another option would be to add File Tools to the Windows Explorer context menu. You select the files and/or folders that you want, then right-click and select "Macecraft File Tools". (This is what WinZip does, for example.)