Funny enough, nearly all corporate jets that have a solid cockpit door have a placard stating "DOOR TO BE OPEN ON TAKEOFF AND LANDING".
The theory behind this is to assure that the door will not jam in case of an accident. Which is rather silly to me, as most cockpit doors in corporate jets are made out of very thin materials covered with thin wooden veneerer. Shoot, you can just lean against a door and it will open. The vast majority of corporate jets just have a cloth curtain to separate the cockpit from the cabin.