IBX-11260: Fixed dropdown lazy initialization for dynamically populated translation selects

[mikadamczyk]

🎫 Issue	IBX-11260

Related PRs:

• https://github.com/ibexa/content-tree/pull/113

Description:

This PR fixes an ibexa.core.Dropdown initialization edge case that caused empty option lists in dynamically populated translation modals (for example, the Content Tree “Add translation” modal).

The regression appeared when a dropdown was initialized while its underlying <select> had no options yet, and the options were added later by JavaScript. In that case, the dropdown instance was left in a partially initialized state and did not properly reflect later option updates.

Root cause:

Dropdown.init() returned early when the source <select> had no options. This prevented full UI initialization (itemsPopover) and also blocked proper refresh behavior for options added later.

As a result, consumers who dynamically rebuild <select> options (like Content Tree translation modal) ended up with:

• native <select> containing correct options
• custom dropdown UI still showing an empty list

What changed

• Introduced deferred/lazy UI initialization path in ibexa.core.Dropdown
• Extracted dropdown UI setup into initializeDropdownUI()
• Attached observers before the "no options" early return
• When options are added later, the mutation observer now:
  • completes dropdown UI initialization (if not initialized yet)
  • then calls recreateOptions()

Why this fix is in admin-ui

The issue is in the shared dropdown component lifecycle, not in Content Tree logic itself. Fixing it in admin-ui removes the need for consumer-level workarounds (manual instance reset / re-init) and benefits any feature that uses dynamically populated dropdown options. If this fix is merged, then https://github.com/ibexa/content-tree/pull/113 should be closed.

Impact

• Fixes empty source language list in Content Tree “Add translation” modal (first open)
• Keeps existing dropdown behavior unchanged for statically initialized dropdowns

For QA:

Documentation:

[KamilSznajdrowicz]

QA Approved - sanities and regression pass

CI Fix here: #1845

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud