How can I move a field in a node edit form from the main region into the advanced/secondary group region in the right-hand column?
This question asks how to move elements out of the secondary group into the main group, but this is the inverse.
I tried setting a group for my field in a similar way to the above answer:
$form['field_article_language_filter']['#group'] = 'advanced';
This did move it, but I'd like it to be in a group with a summary arrow button to toggle it closed or open.