I think that is not possible. Fences don't work like Stardock ObjectDock. Fences is your desktop icons organizer, hence it need to work on desktop level, below the opened Windows area. However, I have forwarded your request to the Stardock Support Team for their review and recommendations. Please keep an eye on this thread for any updates. We really do appreciate your feedback, Thanks
Basj,
Stardock Community Assistant.