bug#21207: 25.0.50; Cursor position behaves unpredictably on the 'display text property

[Eli Zaretskii]

> Date: Fri, 7 Aug 2015 19:31:29 +0100
> From: Artur Malabarba <bruce.connor.am@gmail.com>
> Cc: 21207@debbugs.gnu.org
> 
> I'm using this to visually wrap some lines, but not others (as part of
> rewriting longlines-mode to work without editing the buffer). 
> I can wrap only the lines I want by doing the procedure in item 2 (displaying 
> a
> space as a newline). When the line I'm wrapping happens to be indented, I have
> to use the procedure in item 4 (so the second line gets indented too), and 
> it's
> mildly annoying that I can't place the cursor at the end of the line.

Can you use line-prefix and/or wrap-prefix for that?

It should be possible to support the 'cursor' property on a newline
inside a display string, but not inside an overlay string.  Not sure
if this disparity will not cause confusion and resistance, as we
generally try to support the same features in both cases.

In general, I hoped that line wrap at some constant column other than
the window edge (which is what I understand you are trying to do) will
be implemented on the display engine level, where IMO it belongs, not
by using display properties and such likes.