A pane that has been emptied is showing nothing, but it kept the scroll
position it was left at and went on claiming the render it used to show,
so the next render into it — the same command's output, the file it was
showing being selected again — counted as content the view already had,
and was revealed partway down.
So say what the empty pane is: at the top, and showing nothing that a
render can be a re-render of.
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>