j/k navigation only cycles through h2 headings, ignoring expanded subsections

[kookyleo]

Bug Report

Description

The j/k keyboard navigation only cycles through h2 level headings and does not navigate into subsections (h3, h4, etc.) even when those subsections are expanded.

Current Behavior

• Press j to navigate to next section → jumps to next h2
• Press k to navigate to previous section → jumps to previous h2
• Expanded subsections (h3, h4, h5, h6) are skipped
• Navigation only works at the top level (h2)

Expected Behavior

When subsections are expanded:

• j should navigate to the next visible heading (h2, h3, h4, etc.)
• k should navigate to the previous visible heading
• Navigation should follow the visual document hierarchy
• Collapsed subsections should be skipped (only navigate to their parent)

Example Scenario

## Section 1 (h2) ← j/k navigates here
  ### Subsection 1.1 (h3) ← Should navigate here when expanded, but currently skipped
  ### Subsection 1.2 (h3) ← Should navigate here when expanded, but currently skipped
## Section 2 (h2) ← j/k navigates here
  ### Subsection 2.1 (h3) [collapsed] ← Should be skipped
    #### Subsection 2.1.1 (h4) [hidden] ← Should be skipped
  ### Subsection 2.2 (h3) ← Should navigate here when expanded
## Section 3 (h2) ← j/k navigates here

Steps to Reproduce

1. Open a document with h2 sections that contain h3/h4 subsections
2. Expand some subsections so they are visible
3. Press j or k to navigate
4. Observe that only h2 headings are selected, h3+ subsections are skipped

Technical Notes

• Need to query all visible headings, not just h2
• Should check if heading is within a collapsed section
• Navigation order should follow DOM order of visible headings
• May need to filter based on computed styles or parent section state

Related Code

Likely in:

• Keyboard navigation handler
• Section navigation logic
• Heading selector queries (probably using h2 selector instead of h2, h3, h4, h5, h6)

[kookyleo]

Additional Information

The behavior is inconsistent - navigation into subsections does work sometimes, but not always. The exact conditions that cause it to fail have not been identified yet.

Observations

• Sometimes j/k will navigate into expanded subsections correctly
• Other times it skips subsections even when they are visible
• No clear pattern has been found yet for when it works vs. when it doesn't
• This intermittent behavior suggests a race condition or state synchronization issue

Possible Causes to Investigate

• Timing issue with section expansion and navigation state update
• Event handler registration order
• Cache or state not being invalidated when sections expand/collapse
• Different behavior depending on how sections were expanded (click vs. Expand All vs. initial state)
• Navigation index/cache not being rebuilt after DOM changes

This inconsistency makes the bug harder to reproduce reliably and suggests the root cause may be more complex than just a selector issue.