bug#25308: Shorten long "ui-lines" in Custom buffers

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

>> Custom buffers contain two long lines, the first separating the initial
>> buttons from the options shown below, and the second is for symmetry, I
>> suppose.  This is implemented in `custom-group-value-create'.
>> 
>> These lines are 999 characters long.  When point ends up on the "line
>> line", then it ends up at the *end* of that line, scrolling all content
>> except for the line itself off-window.  This happens both with C-n/C-p,
>> as well as when using the mouse scroll wheel.
>
> The scrolling only happens for me if I set truncate-lines to a non-nil
> value.  Is that what you see?  Or perhaps you invoke Customize in a
> partial-width window, in which case truncate-partial-width-windows is
> non-nil by default?
>
> If lines are not truncated, there's no horizontal scrolling.

I can't reproduce the error, either (without truncate-lines).  But
truncate-lines is not set in Customize buffers by default, so I don't
really think this is a bug.  However, I agree with Jonas that the lines
aren't very pretty.

The worst bit is perhaps that the make the little arrow in the right
fringe appear...  and they aren't symmetrical, since they use
'underline: They're very close to the text at the start, but far away
from the final line of text.

I'd rather just remove those lines completely -- I think that'd be less
busy.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no