Block Editor: Icon picker never initialises in repeater items added inside the editor canvas

[Misplon]

What happens

In the block editor, add a SiteOrigin Hero block, add a frame, add a button inside it, click Choose Icon. Nothing opens. Same with the Price Table block: add a column, add a feature, click Choose Icon. The icon field inside the newly added repeater item never gets data-initialized, so its click handler is never bound.

Reproduced on the 1.74.3 release build and on the published 1.74.2, both in a fresh WordPress Playground, WP 7.1. Not a regression, but the 1.74.3 changelog line "Block Editor: Fixed the icon picker not initializing in newly added or copied repeater items" claims this is fixed and it is not. That line came from commit 30db145, Step 1 of the #2334 Price Table branch, which had no issue of its own.

Why

Three things, each verified live in the editor canvas iframe:

1. base/inc/fields/js/icon-field.js binds sowsetupformfield to the icon field only when window.top === window.self. Inside the canvas iframe the binding is skipped. The iframe document's sowsetupformfield handlers are media, tinymce and location only. So the 30db145 change, which adds the icon field to repeaterImmediateSetupFieldSelector in base/js/admin.js and fires sowsetupformfield, cannot reach the icon field in the block editor.
2. The MutationObserver in icon-field.js that is meant to cover iframes is not running: a bare .siteorigin-widget-field-type-icon element appended to the iframe body stays uninitialised.
3. triggerRepeaterFieldSetup() in admin.js fires sowrepeaterfieldsadded on the iframe's document. compat/block-editor/widget-block.js listens for it on the top document under a per-block namespace. The event never crosses, so the block never re-sends the sowbBlockFormInit postMessage. Posting that message by hand initialises the new icon fields immediately and the picker opens.

Fix

Make the repeater-added signal reach the block in the canvas case, so the existing sowbBlockFormInit path re-runs ensureIconFieldsInitialized(). Either fire sowrepeaterfieldsadded on the top document as well when window.top !== window.self, or have widget-block.js listen on the canvas document. Cover it with a Playground e2e: Hero, add frame, add button, Choose Icon opens.

[Misplon]

Audit: how the original fix shipped without working

Tested on the wrong kind of site. The 30db145 fix was verified on a dev site running Vantage, a classic theme. With a classic theme the post editor does not iframe the canvas, so sowsetupformfield fires in the top window and the one-line fix works. On a block theme the canvas is an iframe, icon-field.js skips its sowsetupformfield binding there (gate added in 8f400d9, Oct 2025), and the fix cannot reach the field. Reproduced on WordPress Playground with the default block theme on both 1.74.2 and the 1.74.3 build.

No safeguard was in place.

• No issue of its own. The icon step was folded into Price Table: front-end render is broken (correct in block editor preview) #2334, a Price Table render report that turned out to be a sidebar layout problem, not a widget bug.
• No test. The branch added 184 lines of PHPUnit for LESS variables and no test for the icon picker. The existing e2e wb-form-field-site-editor.test.js clicks an icon in a pre-rendered form, never one inside a repeater item added at runtime.
• No PR, no review. Merged straight to develop as 2c3d346 on 27 July, self-authored, and Price Table: front-end render is broken (correct in block editor preview) #2334 was closed with "Fixed in admin.js (30db145)" with no reproduction recorded.
• No run record under tasks/runs and no surviving session transcript for the 26 July work.

The event chain it depends on has been broken since May. 867b28f (11 May 2026) fires sowrepeaterfieldsadded on document in admin.js, which is the canvas document when the editor is iframed, while widget-block.js listens on the top document. The event has never crossed on a block theme, so the "event-driven repeater field init" for the iframe has never fired for a repeater add there.

The 1.74.3 release check repeated the gap. The changelog line was verified against git show 1.74.2:base/js/admin.js, which proves the code changed, not that it works. The release human-test gate exercised #2367 only.

Process change for this and future releases. Every changelog line gets a human check on a block-theme Playground built from the release zip, not on the classic-theme dev site.

[Misplon]

Fixed on release/1.74.3, not yet merged or tagged.

• 44d0d1d4 Block Editor: Initialise Icon Fields In Repeater Items Added Inside The Canvas (fix in base/js/admin.js and the e2e tests/e2e/wb-repeater-icon-field-canvas.test.js; carries Fixes #2369, so the release merge closes this issue)
• a5932292 Release 1.74.3 changelog (the changelog line "Fixed the icon picker not initializing in newly added or copied repeater items" now holds for 1.74.3)

Verification on a fresh block-theme Playground from the rebuilt 1.74.3 zip (5,030,687 bytes), canvas confirmed to be an iframe: Hero add frame, add button, Choose Icon opens with data-initialized true and 163 icons rendered; Price Table add column, add feature, Choose Icon opens, and a copied feature row's icon field initialises too. The e2e fails on the unfixed build (data-initialized never set) and passes on the fixed one.

[Misplon]

Correction to the audit: the iframe is not a theme-type distinction

I wrote that a classic theme gives a non-iframed post editor canvas. On WordPress 7.1.1 that is wrong. Tested on Playground with the 1.74.3 build: the post editor canvas is an iframe with a block theme, with Twenty Twenty-One, with Twenty Twenty-One plus Page Builder 2.36.0, with a registered block API v2 block, and with a classic meta box present. Every one of those is the iframe path, so the 30db145 change could not have worked in the post editor on any of them. The only non-iframed block editor surface found is the block-based Widgets screen on a classic theme, where the ordinary sowsetupformfield binding applies.

Verified with the 44d0d1d4 fix, Hero (frame, then button) and Price Table (column, then feature), icon field data-initialized and picker open on click:

Surface	Canvas	Result
Post editor, block theme	iframe	pass
Post editor, Twenty Twenty-One	iframe	pass
Post editor, Twenty Twenty-One, meta box registered	iframe	pass
Site Editor template, block theme	iframe	pass
Widgets screen, Twenty Twenty-One	top window	pass
Copied repeater row, post editor, both themes	iframe	pass

The 44d0d1d4 commit message repeats the classic-theme wording; the e2e is correct because it asserts the iframe directly rather than the theme.