I went to check the locks on the sliding door, and found Kitty on the balcony. Opened the door to offer foody-type-bribes, but unfortunately the opening of the door seemed to startle Kitty, and then Kitty and I spent a few tense minutes regarding one another warily from opposite sides of the railing. Eventually I gave up, left a little heap of salmon treats on the mat (where Kitty had been lying) and shut the door. At least Kitty is resting on our mat, anyway. That's progress.