FileExplorer Shell Extensions and "Folder"

While Folder is an allowed Type within a desktop9:ExtensionHandler when used in desktop9:FileExplorerClassicContextMenuHandler,

the AppInstaller app does not allow Folder as a Type within a desktop9:ExtensionHandler when used in desktop9:FileExplorerClassicDragAndDropMenuHandler.

 

Installing the package with Folder as a DragAndDrop handler results in a failure, complaining that Folder is a restricted system FTA.  Drive and Directory are also a problem.