feat: pass dropPosition to defineContainer's render callback

[christianhg]

Today defineContainer's render callback receives the engine's path-resolved focused/selected/readOnly state for the container, but not the resolved drop position. Legacy block-objects already auto-paint a drop indicator via the engine. Containers couldn't, because the data wasn't plumbed through.

This passes dropPosition: 'start' | 'end' | undefined to the render callback when a drag targets the container's block boundary. Consumers paint their own indicator using whatever DOM and styling they prefer:

defineContainer({
  scope: '$..callout',
  field: 'content',
  render: ({attributes, children, dropPosition}) => (
    <aside {...attributes} data-drop-position={dropPosition}>
      {children}
    </aside>
  ),
})

The resolution reuses the same path-based match the legacy pipeline uses (resolveElementDropPosition). No new engine logic, no new subscriptions, no new public hooks. Containers that don't reference dropPosition in their render callback pay zero extra cost during a drag.

The playground callout demonstrates the pattern with a thin top/bottom border painted via Tailwind data-attribute selectors.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
portable-text-editor-documentation	Ready	Preview, Comment	May 11, 2026 0:27am
portable-text-example-basic	Ready	Preview, Comment	May 11, 2026 0:27am
portable-text-playground	Ready	Preview, Comment	May 11, 2026 0:27am

[changeset-bot]

🦋 Changeset detected

Latest commit: 8663222

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@portabletext/editor	Minor
@portabletext/plugin-character-pair-decorator	Major
@portabletext/plugin-emoji-picker	Patch
@portabletext/plugin-input-rule	Patch
@portabletext/plugin-markdown-shortcuts	Major
@portabletext/plugin-one-line	Major
@portabletext/plugin-paste-link	Major
@portabletext/plugin-sdk-value	Major
@portabletext/plugin-typeahead-picker	Patch
@portabletext/plugin-typography	Patch
@portabletext/toolbar	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

📦 Bundle Stats — @portabletext/editor

Compared against main (1b64415c)

@portabletext/editor

Metric	Value	vs main (1b64415)
Internal (raw)	744.5 KB	+325 B, +0.0%
Internal (gzip)	142.9 KB	+28 B, +0.0%
Bundled (raw)	1.35 MB	+325 B, +0.0%
Bundled (gzip)	303.9 KB	+27 B, +0.0%
Import time	96ms	+0ms, +0.0%

@portabletext/editor/behaviors

Metric	Value	vs main (1b64415)
Internal (raw)	467 B	-
Internal (gzip)	207 B	-
Bundled (raw)	424 B	-
Bundled (gzip)	171 B	-
Import time	2ms	+0ms, +0.6%

@portabletext/editor/plugins

Metric	Value	vs main (1b64415)
Internal (raw)	3.6 KB	-
Internal (gzip)	1021 B	-
Bundled (raw)	3.4 KB	-
Bundled (gzip)	952 B	-
Import time	8ms	+0ms, +0.1%

@portabletext/editor/selectors

Metric	Value	vs main (1b64415)
Internal (raw)	76.3 KB	-
Internal (gzip)	14.3 KB	-
Bundled (raw)	72.4 KB	-
Bundled (gzip)	13.3 KB	-
Import time	8ms	+0ms, +0.2%

@portabletext/editor/traversal

Metric	Value	vs main (1b64415)
Internal (raw)	9.2 KB	-
Internal (gzip)	2.4 KB	-
Bundled (raw)	9.3 KB	-
Bundled (gzip)	2.4 KB	-
Import time	5ms	+0ms, +0.9%

@portabletext/editor/utils

Metric	Value	vs main (1b64415)
Internal (raw)	30.6 KB	-
Internal (gzip)	6.5 KB	-
Bundled (raw)	28.4 KB	-
Bundled (gzip)	6.1 KB	-
Import time	7ms	+0ms, +2.0%

🗺️ . · ./behaviors · ./plugins · ./selectors · ./traversal · ./utils · Artifacts

Details

• Import time regressions over 10% are flagged with ⚠️
• Sizes shown as raw / gzip 🗜️. Internal bytes = own code only. Total bytes = with all dependencies. Import time = Node.js cold-start median.