In the org-mode manual says
Unlike LATEX_HEADER, contents from LATEX_HEADER_EXTRA keywords will not be loaded when previewing LaTeX snippets
If I start Emacs using
emacs -q, it loads
org version 8.2.10 from the shared libraries and the following fragment works fine.
The newcommand has no effect on the preview and when I use
org-preview-latex-fragment I simply get a blank image. However, in
org version 9.0.9, starting
emacs with an empty config file and using
org-toggle-latex-fragment, this fragment creates an image with the text "testing". It is using the command inside the preview (!).
Is it possible to use
9.0.9? I have tried byte-recompiling
org-plus, and my Emacs is being loaded without any initial configuration but I have not been able to use it.