The parking space issue speaks volumes. Ferguson's probably still turning up frequently enough to make this an ongoing dilemma....otherwise, why would anybody give a fuck? An "empty space" set aside for the person who holds the role is just that.
It's not fucking 'haunted' and it's not like it's Ferguson's pipe, slippers and hobnobs somebody wants to re-purpose for themselves, or that cosy, warm side of the bed next to his missus. It's a parking space. Ferguson's got a statue full of birdshit permanently parked outside the ground, and a stand with his name on it.
Perhaps the parking space in question isn't individually 'named' and just says "Manager" in which case, get it named you twats, and let Ferguson and everybody else know [especially Solskjaer] that it's now a transient piece of estate which is automatically inherited by the person the players must currently call 'gaffer.'
I still think it's a combination of Ferguson still turning up however, and Solskjaer being well aware of this, and feeling like a twat displacing him after the many aeons he's been habitually using it.