gettext doesnt recognize/translate the argument of directive

[xSitu]

Not really sure if its a bug or just an issue in my case.

When using gettext, the argument of a directive is not recognized which has to be translated (in my case).

I am using the sphinx-panels extensions Github , ExampleSite especially to use the dropdowns.

Example:

.. dropdown:: english should be translated to .. dropdown:: german since the argument "english" refers to the dropdown_title

PoEdit ist recognizing the content of the toggle-able container but not the dropdown_title.

I was looking for a workaround and after i saw this post gettext Substitution i tried to use substitutions like this:

.. dropdown:: |SubstitutionTest|

   abc

.. |SubstitutionTest| replace:: German

I was hoping that gettext would recognize "German" in line .. |SubstitutionTest| replace:: German so i could adjust it in PoEdit but it also didnt work.
Is there any way to work around/fix it?

[tk0miya]

The i18n feature of Sphinx extracts translation messages from doctrees that are intermediate data on building Sphinx project. In other words, it does not read the source mark-up files directly. To translate it, you need to modify the extension to support translations.

To support translations, please make your node class to a subclass of sphinx.addnodes.translatable class and overrides their methods for translations.
https://github.com/sphinx-doc/sphinx/blob/3.x/sphinx/addnodes.py#L51