bug#27014: 26.0.50; auto-hscroll-mode and tabulated-list-mode

[Eli Zaretskii]

> From: Stephen Berman <stephen.berman@gmx.net>
> Date: Mon, 22 May 2017 01:06:50 +0200
> 
> 0. emacs -Q
> 1. Set auto-hscroll-mode to `current-line'.
> 2. Visit a buffer that uses tabulated-list-mode, e.g. Buffer Menu (C-x
>    C-b), Package Menu (M-x list-packages), Proced (M-x proced), making
>    sure that the buffer contains at least one truncated line and a line
>    below it.
> 3. Advance point along the truncated line (e.g. by repeating C-f or M-f
>    or with C-e).
> => When point gets within hscroll-margin columns of the right window
>    edge (or further), instead of the current line being scrolled, the
>    one below it is.

Ah, yes: the header line and its confusing effect on the display
iterator geometry.  Should be fixed now.

> (In addition, with Proced, the header line is also scrolled, but that
> seems to be a Proced bug

It looks like a feature: Proced scrolls the header line to keep the
column headings in sync with the hscroll.