Something is still wrong with your DnD code.
I recorded a short screencast.
In this cast I just do a quick sort of items and do a real short DnD operation.
As you can see the items seems to get randomly assigned to contexts, converted to projects or starred.
Depending what menu item is on the same vertical position on the left panel the item technically gets dropped there although my mouse completely stayed in the main panel.
(You can’t see my mouse but it’s really staying horizontal at the somewhat same x-position)