bug#54800: 28.1; calc: Cursor positioned at weird position in calc stack

[Christoph Arenz]

> And there are still cases where above does not work correctly.
> E.g. when using a theme which has different line heights for header
> line and mode line than for text lines,
> say M-x load-theme leuven .
>
> Approaching it differently seems to cover those cases as well:
>
>     (vertical-motion (- 1 (window-body-height)))

N.B.
This works for me as long as line-spacing is nil.
For non-nil there seems to be a bug in window-body-height.
I have opened bug report #54894 for that.