ACF Chat Fridays give the Advanced Custom Fields community a chance to hear directly from the team behind the plugin. The September session focuses on reacting to editor changes in WordPress 7.1, navigating the ACF PRO 6.8.9 release, and getting the most out of ACF Blocks v3, inline editing, and custom toolbar controls.
Whether you are managing existing client builds on ACF Blocks v2 or looking to streamline content editing workflows with true inline editing, this session provides actionable tips and technical demos to keep your custom block workflows smooth and future-proof.
Hosted by Iain Poulson, Phil Johnston, Matt Shaw, and Anthony Burchell.
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Session recording
Watch the full session below or jump to the highlights in the summary.
Session summary
Our discussion covers everything from handling iframe changes in WordPress 7.1 to customizing the editing experience inside Gutenberg. Key topics include:
- WordPress 7.1 & Canvas changes: Why WP core enforces iframe isolation and how it affects block editor rendering.
- ACF PRO 6.8.9 release: Addressing legacy block compatibility and editor layout shifts.
- ACF Blocks v2 Compatibility Plugin: A standalone workaround to restore legacy Edit Mode on demand.
- Mastering ACF Blocks v3: Leveraging the Expanded Editor Panel for complex fields and repeaters.
- Fine-tuning UI via block.json: Hiding cramped sidebars and controlling button placement.
- Inline editing & toolbar controls: Enabling zero-JS visual editing and custom toolbar buttons.
- Community Q&A: In-depth answers on Local JSON, multi-post-type field groups, and smooth block migrations.
Why Canvas Edit Mode shifted
WordPress 7.1 introduces stricter iframe isolation within the Block Editor canvas. In older versions of Gutenberg, styles from WP Admin often leaked into the block preview area—for example, rendering administrative blue buttons inside the canvas preview instead of actual front-end styling.
To isolate bleeding from CSS and JavaScript, WordPress software forces iframe rendering across blocks. However, this change directly impacts ACF Blocks v2 “Edit Mode”—where field forms display directly inside the block canvas preview. Because administrative forms cannot render within the front-end canvas iframe, WordPress 7.1 automatically pushes these field inputs into the editor sidebar, creating a cramped experience for complex field groups such as repeaters, Flexible Content, or WYSIWYGs.
The ACF Blocks v2 Compatibility Plugin
For agencies maintaining existing client sites where content editors rely on the classic inline form layout, the ACF team released an interim workaround alongside ACF 6.8.9.
ACF Blocks v2 Iframe Compatibility Plugin: A separate plugin available via GitHub that restores legacy v2 Edit Mode behavior inside WordPress 7.1.
While this plugin provides a safety net for legacy builds, the ACF team emphasizes that it is a temporary workaround. As WordPress software continues to evolve, developers are strongly encouraged to migrate custom blocks to ACF Blocks v3.
Upgrading to ACF Blocks v3: The expanded editor
Originally introduced in ACF 6.6, ACF Blocks v3 replaces canvas form editing with the Expanded Editor Panel—a spacious flyout interface designed specifically for managing complex field groups without crowding the editor canvas or relying on a narrow sidebar.
If your block does not explicitly define an ACF version in its block.json file, ACF automatically defaults to Blocks v3 when running on WordPress 7.1.
Customizing block UI in block.json
Blocks v3 gives developers precise control over how field forms and preview buttons appear in the block editor. You can configure these settings directly inside your block’s block.json file:
JSON
{
"name": "acf/testimonial",
"title": "Testimonial",
"acf": {
"mode": "preview",
"blockVersion": 3,
"hide_fields_in_sidebar": true,
"render_preview": true,
"expanded_editor_button": ["toolbar", "sidebar"]
}
}Key attributes introduced for Blocks v3 customization include:
- hide_fields_in_sidebar: Set to true to remove field inputs from the right sidebar entirely, avoiding cluttered form controls.
- render_preview: Set to true to maintain visual block rendering in the canvas while editing fields elsewhere.
- expanded_editor_button: Pass an array defining where the Expanded Editor launch button should appear ([“toolbar”], [“sidebar”], or [] to hide it entirely).
Inline editing & top toolbar controls
First introduced in ACF 6.7, inline editing transforms block previews into true visual editing surfaces. By turning on auto inline editing in your block.json, ACF automatically scans your render template for field values (like get_field()) and makes them editable on click:
JSON
{
"name": "acf/testimonial",
"title": "Testimonial",
"acf": {
"mode": "preview",
"blockVersion": 3,
"auto_inline_editing": true
}
}Best of all, inline editing works entirely through PHP helper functions in your render templates. It requires no JavaScript build step, no React code, and no complex dependencies.
Custom top toolbar fields
For fields that lack a direct visual element on the page, such as background color pickers or layout switches, you can map ACF fields directly to the block’s top toolbar using the acf/blocks/top_toolbar_fields PHP filter:
PHP
function my_block_top_toolbar_fields( $fields, $block ) {
if ( $block['name'] === 'acf/testimonial' ) {
$fields[] = array(
'field' => 'background_color',
'icon' => 'art',
'label' => 'Background Color'
);
}
return $fields;
}
add_filter( 'acf/blocks/top_toolbar_fields', 'my_block_top_toolbar_fields', 10, 2 );This allows editors to click a simple toolbar icon to toggle block options in a quick popover window, avoiding long field forms entirely.
Learn more about ACF and AI
WP Engine’s Iain Poulson spoke with The WP Minute about ACF’s future and how the plugin is developing for the AI era. Click here to learn more!
Resources & links
Our next ACF Chat Fridays session is scheduled for October 9, 2026. In the meantime, make sure to fill out our 2026 Annual ACF Community Survey! We want your feedback to help shape the future roadmap of ACF!
Register for the next session of ACF Chat Fridays →
Tag or message us on X with suggestions or feedback using #ACFChatFridays.
