I wonder what the earliest image of the 6th floor window is that day? There would be no obvious reason to take a photo or film of the TSBD prior to the assassination but it might have been caught inadvertently. I don't recall anyone who worked tjere ever being asked who opened the 6th floor window. Presumably it was Oswald but if that area was used as a smoking area as sometimes mentioned, then who knows? Maybe someone else did it earlier that morning. I assuming the windows were not left open at night and that someone opened it that day. Mostly a curiosity but it would provide some insight into Oswald's mindset to know what time that occurred if he opened it. Oswald was a meticulous planner in the Walker situation. Have to presume that he scouted it out beforehand. What if he sets up to assassinate JFK only to discover that window wouldn't open?