win7 Pro (on multiple builds on multiple machines)
my ASCII is equivalent to the issue shown. my Ascii is my image.
Your procedure of events is not working for me on any of my windows machines to recognize desktop edge. it recognizes the top that way. but not the bottom.
Neverrrr-miiiiind i opened C:\Users\USERNAME\Application Data\Stardock\Fences\Backups\ "DailySnapshot0.xml"
and deciphered the data there. Edited it, and restored from it. and now its docked like the other items on the top. but on the bottom and rolls up into the desktop as desired. Even when not docked to the desktop edge.
¯\_(ツ)_/¯ Yay for the hacker approach.