bug#1503: feature request: multiline header (and mode) lines

[Stefan Kangas <stefan@marxist.se>]

martin rudalics <rudalics@gmx.at> writes:

> IIUC the OP would be better served with a separate buffer for listing
> these subdirectories shown above the window of his buffer.  To glue them
> together, the two windows could be put into an atomic window.  Omitting
> all decorations for that separate buffer, it would not be discernible
> from a header line.
>
> So if you see any use for a multi-line header line, please give me
> details where a specification via 'header-line-format' would be
> preferable to one that puts that stuff into a separate buffer.

One benefit of the header line is that it always stays in place, whereas
with a buffer you never know where it might end up.  Or is there a way
to force a buffer in place with the same strong guarantee?

We also might not want users to switch to that buffer, as it would be
more annoying than useful (e.g. headers in tabulated-list-mode).  AFAIU,
with a regular buffer you will always be able to switch to them with
`other-window'.

I was also going to say that with header-line-format you get horizontal
scrolling automatically, but it turns out that you don't.  In any case,
it seems like this feature shouldn't be too hard to add.  (I remember
now that I added code to fix that in one of my packages.)