Sidebar Navigation Arrows Not Rotating on Click in Jupyter Book

[mscharling]

Describe the bug

Context
When I navigate the sidebar in Jupyter Book by expanding or collapsing sections.

Expectation
I expected the arrows next to the sidebar items to rotate or change direction, indicating whether the sections are expanded or collapsed.

Bug
But instead, the arrows remain static and do not change their orientation, regardless of the section's state. This issue persists across different chapters and is unrelated to specific content. There is no error message in the console related to this, but it's a UI inconsistency.

Problem
This is a problem for users because the static arrows can cause confusion about the current state of the navigation menu, impacting the user experience and making navigation less intuitive. It is especially challenging for new users who rely on visual cues for navigation.

Video of problem
https://gyazo.com/e361209eae5e552e4375206540b03752

Reproduce the bug

1. Set up a Jupyter Book with multiple chapters or sections, ensuring that some chapters have sub-sections.
2. Open the Jupyter Book in a web browser.
3. Locate the navigation sidebar which contains the chapters and their expandable sub-sections.
4. Click on the arrow next to a chapter title to expand or collapse the sub-sections under that chapter.
5. Observe the behavior of the arrow icon next to the chapter title during this interaction.

List your environment

Jupyter Book : 0.15.1
External ToC : 0.3.1
MyST-Parser : 0.18.1
MyST-NB : 0.17.2
Sphinx Book Theme : 1.0.1
Jupyter-Cache : 0.6.1
NbClient : 0.7.4

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