Collapse the content under a heading

Hover a heading to see ▼ on its left. Click it to collapse everything under that heading (up to the next heading of the same or a higher level); it turns into ▶. Click again to expand.

Works in both reading and edit mode. The app remembers what you collapsed until you quit it, and nothing is written to the note file (exports and printing are not affected).

Searching with ⌘F or jumping from a table of contents or a heading link opens collapsed sections automatically.