Disappointing, but at least we got to know that Tadano is finally starting to read the situation. Dude's like a camera that can see everything but itself until someone shoves a mirror in its face.
I'm guessing the bottle at the window was something Ichi gave her earlier and she didn't want him to realize it. Maybe the milk tea from that time she was crying?
Also, mama is actually adorable wtf
Edit: yup, it's the milk tea bottle https://mangadex.org/chapter/820757/4
...oh. OH! I completely missed the shadow thing. I thought the joke was that she took the pic and immediately sent it to her even though they're right next to each other.