Entity Reference Tab / Accordion Formatter

Entity Reference Tab Formatter adds an accessible tab/accordion formatter for
entity_reference and entity_reference_revisions fields. It pairs nicely with
Paragraphs but works with any referenced entity type.

• Switch between Tabs or Accordion layouts without touching stored data.
• Map tab titles to any referenced field, with a fallback to the entity label.
• Render bodies as a single field, the full referenced entity (view-mode aware), or any Views block display (supports contextual filter arguments).
• Tune accordion behaviour (single vs. multiple open items, header color/width, icon alignment).
• Lightweight JavaScript built on Drupal core once(); no jQuery UI dependency.
• Accessible markup and keyboard defaults keep the first panel visible even before scripts load.

Installation

1. Install with Composer.
2. Enable via Extend or run drush en entity_ref_tab_formatter.
3. Clear caches.

Configuration

1. Open Manage display for the entity reference field (e.g., a Paragraph reference field).
2. Pick Entity reference tab formatter in the Format column.
3. Adjust the settings:
   • Tab title field – choose the field to display in the tab/accordion header; falls back to the entity label when empty.
   • Tab body field – select a specific field, choose Views block (then pick a block display and optional comma-separated contextual arguments), or use Rendered entity (full view).
   • Rendered entity view mode – when rendering the full entity, select the view mode configured under Structure → [Bundle] → Manage display.
   • Display style – toggle Tabs vs. Accordion and set accordion options (single/multiple open items, header color, full-width header, icon alignment).
4. Save and clear caches if needed.