bug#41965: 26.3; weird behaviour of 'scroll-down-line'

[cage]

On Sat, Jun 20, 2020 at 09:59:47PM +0300, Eli Zaretskii wrote:

Hi Eli!

> [Please use Reply All to keep the bug address on the CC line.]

Sorry, again!

[...]

>
> OK, now I see what you see.
>
> However, this is the expected behavior: Emacs cannot display a window
> with the window-start position inside a display property.  If you
> trick Emacs into doing that, you get what you describe.
>
> Instead of "M-x scroll-down-line RET", you need to scroll 2 lines at
> that point, as in "C-u 2 M-x scroll-down-line RET".

Yes, that's what a clever user of annotate.el actually did! :)

> You need to make
> the window start before the display property.
>
> This is not a bug, just a known limitation of the current display
> code.

Thank you for  clarifying this, i suspected this could  not actually a
bug but  i needed  some more information  from people  with experience
with the Emacs internals to be sure what was happening.

Thank you again for your kind and quick reply and for your work! :)

Bye!
C.