Fix: Prevent box menu from duplicating its items on repeat render (fixes #242)

[swashbuck]

Fixes #242

Fix

BoxMenuView.addChildren() renders all children in a single pass and appends them to the container, but had no guard against being called again after the menu had already rendered. Anything that re-triggered child rendering (for example Trickle's trickle:kill event, which Dev Tools fires via its "Complete menu" button) caused a second full set of items to be appended, so every topic appeared twice.

Added an early return when child views already exist for the view instance. A freshly constructed view (e.g. when revisiting the menu) has no child views yet and still renders normally; only the redundant repeat call is skipped.

Testing

1. Use a course with the box menu and Dev Tools enabled.
2. Open the menu, open Dev Tools, click "Complete menu".
3. The menu items should no longer be duplicated.

Or in the console:

const Adapt = require('core/js/adapt').default;
Adapt.trigger('trickle:kill'); // item count should stay the same

Verified in Framework v5.56.2: with the fix, re-running addChildren() and firing trickle:kill both leave the item count unchanged (12 -> 12). Reverting the guard reproduces the doubling (12 -> 24).

Posted via collaboration with Claude Code