Strange behaviour- anyone experienced this before?

[My Boys M&D]

My gelding is generally very laid back, friendly and likes a good cuddle. However, he HATES anyone standing near his stable door when he is in his stable. He pins his ears back and tries to put his nose right up in your face and if you don't get out of his space he shakes his head, shows the whites of his eyes and snaps. He has never bitten me but he has bitten another lady on my yard. In a way he is good because he only snaps or tries to bite if you repeatedly ignore his requests to p*** off.

The odd thing is that he never shows this behaviour in any other situation. If you open the stable door he becomes happy as larry and will quite happily stand with the door wide open while I brush him/ tack him up. He is absolutely fine in his stable. He just doesn't seem to like having a door separating him, although he doesn't display this behaviour in his field- he will stand and have a cuddle over the gate before joining his chums.

I have owned him for 4 years (he is now 9). Prior to this he was in Ireland. He has been like this as long as I've had him and he has never (as far as I'm aware) been hit/ beaten. Even if he was in his previous home, he has been with me for 4 years now and he clearly trusts me, he follows me everywhere in the field, nickers to me when I arrive and we have a very strong bond. He LOVES other horses and is always very friendly with them- I've never seen him put his ears back at another horse. I have kept him at 3 different yards (indoor and outdoor stables, bars and no bars) and he has been the same in all of them.

Any ideas?!?! I am baffled!

 

[scats]

I had a mare exactly the same. Shut the door and she was rancid, open the door and she was all sweetness and light.

The hooligan is grumpy in his stable and has bitten me quite badly before. But outside of his stable, he's the nicest chap you could meet.

 

[maximoo]

I've one exactly the same he does it as though to say my space ****** off but if I stand there he puts his ears forward and nuzzles to me it's an attitude think , in stable super goes out fine great in field he's 3 has done it to my other gelding to me it's a challenge as once he's out my other boy soon puts him in his place then he stops and just grazes