NOTE: As noted in T337286 there is no stable API for accessing headings but given this regression we might want to re-prioritize that ticket.
Steps to replicate the issue (include links if applicable):
- Enable Parsoid read views using ParserMigration (or office.wikimedia.org which is the only production site using this)
- Visit a long page with many sections
- Scroll down
What happens?:
Table of contents does not change at all
What should have happened instead?:
Table of contents should bold and expand the section you're currently on
Software version (skip for WMF-hosted wikis like Wikipedia):
Other information (browser name/version, screenshots, etc.):
If the current URL has an anchor, that section does get highlighted, althought that too does not get updated when scrolling (unless you scroll to the very top).