When I search in an HTML book created by bookdown, I can only move (up/down arrows) through matches in that section. Is that by design? I have to click on each section to search them?

Example book:
https://jupyter4edu.github.io/jupyter-edu-book/#

Description of problem:
jupyter4edu/jupyter-edu-book#102