If you want to get deep.. <g
My experience is that when the X is clicked, it means "this is not what I
expected to see. i don't know or care what this is, but i'm sure it's
useless to me now. make it go away". Which may or may not be the same as
Cancel, depending on what Cancel does. Probably the same thing most of the
times, so you're right.

Best wishes Harald

"Jon Peltier" skrev i melding
...
Rather than disable it, have it call the cancel button's code. That's what
users
expect it will do, right?