Hi! I just bought a house and my 11 year old cat is indoor only. Our neighbors have two cats who are indoor/outdoor and they have a kitty door so they are outside whenever they want. A few months ago one of the cats started sitting on my back porch and looking through the sliding glass door. My cat would get very upset and lunge at the glass door and scream and howl. Neighbor’s cat won’t flinch, even when I go outside and shoo him away. In a pinch, I taped up a sheet to keep her from looking outside. I don’t have blinds or curtains on my sliding glass door, and I really don’t want to get them, but it seems I might have no choice. Every time I take the sheet down, the cat comes back eventually and gets the same ugly reaction out of my cat. This has been going on since at least October. After he’s been around she is always stressed and hangs out by the door. She obviously feels very threatened and I’m worried if I just let her do her thing she might pee on the door or floor. Is there anything I can do about this besides blinds? I’m frustrated and feel bad for my cat!