I'm experiencing an issue where the Featured Image panel is completely missing from the Gutenberg post editor sidebar. This affects ALL post types (standard posts and custom post types).
Environment:
- WordPress 6.8.5
- PHP 8.2.29
- Toolset Types 3.6.1
- Toolset Blocks 1.6.21
- WPML Multilingual CMS 4.9.2
- Theme: GeneratePress
The problem:
The Featured Image option does not appear in the editor sidebar, and it's also missing from the Preferences > Document Settings panel entirely. Featured images still work correctly on the frontend — they display as expected. The issue is only in the editor backend.
Debugging steps I've already taken:
1. Checked Preferences > Panels: Featured Image is not listed at all.
2. Checked wp_usermeta (wp_persisted_preferences): The entry is clean — 'featured-image' is listed in openPanels and inactivePanels is empty. So it's not a user preference issue.
3. Confirmed post_type_support: Thumbnails work on the frontend, so the post type support for 'thumbnail' is registered correctly.
4. Debug logging with add_meta_boxes hook: A check at priority 9999 confirms that the 'postimagediv' meta box is being REMOVED by something before my check runs. After I re-add it via add_meta_box(), the log shows it exists — but the Gutenberg panel still doesn't appear because Gutenberg uses the REST API, not meta boxes.
5. Attempted fix via wp_loaded: Adding add_post_type_support('post', 'thumbnail') at wp_loaded with PHP_INT_MAX priority did NOT restore the panel.
6. Attempted fix via rest_api_init and admin_init: Same approach, also did not work.
7. Toolset Post Type settings: I've checked Toolset > Post Types — Featured Image IS enabled under 'Sections to display when editing' for all affected post types.
8. PHP deprecation warnings: The debug log shows repeated str_ireplace() deprecation warnings originating from toolset-blocks/vendor/toolset/toolset-common/inc/autoloaded/wpml/WpmlService.php line 915 (null passed as parameter on PHP 8.2). These appear immediately before the featured image removal is detected in the log.
Could you please investigate what in Toolset Types/Blocks is removing the featured image panel from the Gutenberg editor, and how I can resolve this?
Thank you for your help.
