bug#34038: 26.1; set-window-start sometimes fails to set window start

[Markus Triska]

Eli Zaretskii <eliz@gnu.org> writes:

> describing what you thought should have happened here, step by step,

My expectation is that, when the snippet terminates with the message
that window-start is unexpectedly at a position different from 1, and I
*then* do:

    M-: (set-window-start nil 1) RET

that the window-start is set to 1. However, in such cases, at least on
my machine and in the cases I found, the window start is *not* set to 1,
but unexpectedly retained at a position different from 1.