The one thing I can tell you that I have learned with my cats....... Our youngest was trying for a little while and she would always try so my husband would walk through the door and she would dart and I would be outside and make startling noises with a mixing spoon and a cookie sheet something loud and obnoxious that would startle her and it would it only took a few tries and she learned pretty quick that there is something really scarey and noisy outside and she is more than NOT interested in seeing what is going on out there. Is you kitty a male or Female?? If he is a male and unneutered there may be a female outside trying to lure him out. If he was neutured that would stop the urge to search. You could try...... It worked for me.....