bug#24169: 25.1.50; Line numbers disappear when horizontally scrolled

[Noam Postavsky]

On Sat, Aug 6, 2016 at 1:47 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: ivan <ivan.brennan@gmail.com>
>> Date: Sat, 6 Aug 2016 12:02:09 -0400
>>
>> Using linum-mode displays line numbers to the left of the left fringe. I 
>> would expect them to remain visible
>> regardless of any horizontal scrolling, since that's how the left fringe 
>> behaves (not to mention numerous other
>> editors and applications). However, when using line-truncation, the line 
>> numbers disappear when the text is
>> horizontally scrolled. I think this is worth fixing, because it would be 
>> more useful and look better (the dead
>> space takes up screen real-estate and makes me sad).
>
> It's a bug in the design of linum-mode: it puts the overlay that
> displays the line numbers on the first character of each line.  So
> when that first character is not displayed, the overlay is not shown
> either.
>
> A possible fix would be to move the overlay to the first visible
> character after the horizontal scroll.  Patches welcome.

Wouldn't it be simpler to put the overlay over the whole line, so it
doesn't need to be moved?