That is the one.
I happened upon it by chance. I had turned on the TV late on Saturday night and was on TCM which had just begun to play this movie. I came into a little late but with Margot Kidder in it and the odd plot description along De Palma directing and Bernard Hermann scoring it, I stuck around and kept watching it. De Palma definitely brings the crazy in it and it's like he's mashing up a whole bunch of Hitchcock movies into one with this film like a combination of Psycho, Rear Window, and Spellbound. Still remember it when I think of Margot Kidder so it left some kind of an impression.