The WMF core features team tracks this bug on Mingle card https://mingle.corp.wikimedia.org/projects/flow/cards/473, but people from the community are welcome to contribute here and in Gerrit.

You just need to use a mw.hook to which page content handlers like sortable tables and collapsible divs are hooked.

Basically one line: mw.hook( 'wikipage.content' ).fire( $insertedContent );

(You can grep core for mw.hook( 'wikipage.content' ) for usage examples.)

I am a student participating in Facebook Open Academy that's going to work on Flow. I think I will take this to get myself started and get familiar with tools.

Change 112126 had a related patch set uploaded by Legoktm:
fire wikipage.content hook on new posts

https://gerrit.wikimedia.org/r/112126

Change 112126 merged by jenkins-bot:
fire wikipage.content hook on new posts

https://gerrit.wikimedia.org/r/112126