Describe the bug

context

Here is a sample page I've written using the executable book theme:

https://mvanier.github.io/test/content/Test.html.

Click on one of the entries on the right sidebar.

expectation

I expected the page view to switch to that section of the page (which occurs).
I also expected that the correct section title would be highlighted (boldfaced); this does not occur.

bug

Instead, the entry one above the selected section is highlighted (boldfaced).

Reproduce the bug

1. Go to https://mvanier.github.io/test/content/Test.html.
2. Click on the second entry in the right sidebar ("Section 2").
3. Notice that the first entry in the right sidebar ("Section 1") is highlighted instead.
4. Repeat this for any other entry in the right sidebar; in every case but the last, the entry that is highlighted is one up from the entry that is clicked on.

List your environment

sphinx-build: 4.5.0
python: 3.10.1
OS: MacOS Monterey, version 12.4
Browsers tested: Firefox 109.0.1, Chrome 109.0.5414.119
Custom CSS: No
Markdown format: Restructured Text

requirements.txt file:

alabaster==0.7.13
Babel==2.11.0
beautifulsoup4==4.11.1
certifi==2022.12.7
charset-normalizer==3.0.1
docutils==0.17.1
idna==3.4
imagesize==1.4.1
Jinja2==3.1.2
MarkupSafe==2.1.1
packaging==23.0
pydata-sphinx-theme==0.8.1
Pygments==2.14.0
pytz==2022.7.1
PyYAML==6.0
requests==2.28.2
snowballstemmer==2.2.0
soupsieve==2.3.2.post1
Sphinx==4.5.0
sphinx-book-theme==0.3.3
sphinx-copybutton==0.5.1
sphinx_design==0.3.0
sphinxcontrib-devhelp==1.0.2
sphinxcontrib-htmlhelp==2.0.0
sphinxcontrib-jsmath==1.0.1
sphinxcontrib-qthelp==1.0.3
sphinxcontrib-serializinghtml==1.1.5
sphinxcontrib.applehelp==1.0.3
urllib3==1.26.14