Entry type groups in CKEditor fields (settings UI + “Add nested content” menu)

[DanielJackson-Oslo]

Filed by Claude (Claude Code), writing on behalf of @DanielJackson-Oslo, whose site ran into this. The specifics below come from reading craftcms/ckeditor 5.6.1 and Craft 5.10.8.1 locally and building a working prototype — please have a human or a second model verify them. The underlying need is real: the prototype is in daily use on our site.

Problem

A CKEditor field with many nested entry types renders them as one flat, unsorted list — both in field settings and in the “Add nested content” (+) menu. We have 14, so authors scan a single 14-item column to find a block.

Ask

Support EntryType::$group for CKEditor fields, the way Matrix already does:

1. Field settings — render Craft's Craft.GroupedEntryTypeManager (the Matrix group manager: add/rename groups, drag entry types between them, drag groups to reorder) instead of the flat component select.
2. “Add nested content” menu — emit type: 'group' list item definitions so CKEditor renders ListItemGroupView subheaders. The bundled CKEditor 5 (48.x) supports this already.

Screenshots

Before

After: Grouped menu

After: Field settings group UI

Notes from the prototype

Four things any implementation runs into:

1. Field::entryType() builds usages without original, and EntryType::getUsageConfig() only writes group when original is set — so the group silently doesn't persist. (Craft side: Grouped entry type manager is hard to reuse outside Matrix (3 small blockers) cms#19379.)
2. FieldSettingsController::actionApplyEntryTypeIndicators() rebuilds a chip's config from toArray(['id', 'name', 'handle', 'expanded']), so group is dropped on every indicator round trip — on init, and on expand/collapse.
3. _field-settings.twig polls #entry-types for a single data('componentSelect') to drive the image entry type field; a grouped layout has one select per group.
4. CkeEntryTypeSelectInput and Craft.GroupedEntryTypeSelectInput are sibling subclasses of Craft.EntryTypeSelectInput, so a grouped CKEditor select needs both sets of behaviour. Instantiating the plugin's select and then replacing it with a grouped one also left a drag handler that threw at ComponentSelectInput.js:133 (Cannot read properties of null (reading '$targetItem')) on the next drag; we worked around it by never instantiating the plugin's select in the grouped layout. We didn't chase the root cause, so treat that one as an observation rather than a diagnosis.

Related: craftcms/cms#19379 — three details that currently tie the group manager to Matrix.

Happy to open a PR if you'd take one.

[linear-code]

PT-3408