Stuart Ullman sits in front of a window to an exterior view impossible when compared to the layout of the hotel suggested by the previous tracking shot. With this window we are given clear evidence the hotel contains illusions, and more importantly that Jack trusts these illusions as real from the first moment he interacts with them. It's like he's always been here.

JACK Mr Ullman, I'm Jack Torrance
ULLMAN Oh, well come on in, Jack. Very nice to meet you