I mean, yes, they have gotten closer recently and sort of shared space as long as there's space between them. For instance, they are both sleeping on the couch at the moment, one on each end. A whole cushion separates them, and that seems to be the minimum tolerable distance.
But to see out the door, Star had to breach the cushion length distance.
Leo: I know you're out there Mr. Squirrel...
At this point, Leo was still unaware that Star had stepped up to peer over his shoulder.
Star: Why don't you move and let me spot him...
Once Leo discovered she was there, he got scared. He didn't think there was a way out, he was trapped. Slowly, he turned and tried to eye his cat tree. Finally he decided it was worth making a run for it. And she made sure he would not make the mistake of getting in her way at the door again.
Star: ..And stay out!
That's as far as the chase went, she barely set a paw on him. No kitties were harmed in the photographing of this picture!
Star then gained control of the door and went on squirrel patrol while Leo continued his watch from the window. So all's well that ends well.
Oh, and once more, they're close enough that you can see how very tiny Star is compared to big boy Leo.
Have a good, conflict free, weekend!