Cary Grant?

[ImLostAgain]

Discussing old films last night and I seem to remember one in which the star (Grant?) played an amnesiac. Near the end of the film it showed him, in flashback, arguing with a man who steps back and falls out of the skyscraper window. This obviously results in (Grant) being in total shock then calmly putting on his hat and leaving the room and having no memory of the incident.
Was it Cary Grant? Was it someone else? What was the name of the film? Or am I losing my mind?

[Prudie]

It's not Spellbound with Gregory Peck is it?
https://en.wikipedia.org/wiki/Spellbound_(1945_film)

[THECORBYLOON]

Mirage
https://en.m.wikipedia.org/wiki/Mirage_(1965_film)

[ImLostAgain]

Prudie, that's what I thought at first but, no.
THECORBYLOON, that's the one. Brilliant find, it's been doing my head in.