Fabrice Popineau <fabrice.popineau@gmail.com> writes:
> In org reference, 12.7.2, it is said that:
>
> ‘LATEX_HEADER’
> Arbitrary lines added to the preamble of the document, before the ‘hyperref’
> settings. The location can be controlled via org-latex-classes.
>
> Note the plural to lines. How can several lines be specified? AFAICS, if I
> do :
>
> :EXPORT_LATEX_HEADER: \usepackage{mathptmx} % rm & math
> :EXPORT_LATEX_HEADER: \usepackage[scaled=0.90]{helvet} % ss
>
> The second line will take precedence over the first one.
The manual reference is about keywords, i.e, #+LATEX_HEADER:. You are
using properties. The two are slightly different.
In particular, each value from a #+LATEX_HEADER keyword becomes a new
line whereas new values from properties replace the old ones (hence the
PROP+ syntax).
Long story short: if you want multiple lines, use keywords.
There is no
support in multi lines properties in Org. Moreover, the use cases are
sufficiently rare that I don't even think it is worth implementing.