Hi justifun im so sorry for late response, i was unable to get connected to internet lately... well i reviewed plugin functionality and for me it works good... you refers to changing edge docking during runtime, or do you mean set the edge in the editor and on start of layout its fails to dock object?... or maybe you could send me a .capx with the fail... ¿did you dowloaded the last version?
Edit: i forgot mention this, this plugin takes always the the last position of object as reference for docking and saves it internally, so when you disable the behavior its returns to that last position. If you sets param "keep size" to Enabled, the object wont be resized when docking and its will move to the chosen edge using actual coordinates as reference, e.g. if you docks to right and object is currently positioned at x=100, y=200, and have width = 100 and height = 50, will dock to the right at same Y coord in this case 200, and will have x = viewportrigth - width.