That demo is partially faked - if you look at the "plan B" button, it doesn't actually make the UI show some newly changed data, it simply hides the entire wind

That demo is partially faked - if you look at the "plan B" button, it doesn't actually make the UI show some newly changed data, it simply hides the entire window, and shows a different pre-made static window. Even the "plan A" button code doesn't show the only interesting part of the code - how the UI is actually updated in response to the changed underlying data.