I had the same problem. What worked for me is rollback to WP version 6.5.5 using this plugin WP Downgrade | Specific Core Version and the sidebar plugin will work again. You should back up your site before downgrading but I have done this many times and not yet had a problem.
Same problem. After following the suggestion to downgrade WP to 6.5.5 I was able to access the sidebars again. But that’s not really a long-term solution. Will there be an upgrade to be compatible with WP 6.6.x?
Hey folk’s
Same Problems here but i managend to localize the Problem.
In WP 6.6 “wp-pollyfill” is no longer enqueued as a dependency of react, so we have to manually add it. See also WP Core Changeset 57981
I fixed it by adding the ‘wp-pollyill-inert’ and ‘regenerator-runtime’ to the admin_asset.php under src/dist/ in the plugin folder. Tested with WP 6.6.2
<?php return array('dependencies' => array('react', 'react-dom', 'wp-api-fetch', 'wp-components', 'wp-data', 'wp-data-controls', 'wp-element', 'wp-i18n', 'wp-polyfill', 'wp-url', 'wp-polyfill-inert', 'regenerator-runtime'), 'version' => 'e840dbccb709b08f13705356131ec424');
There are also warnings in console that has to be fixed in the future, if the developer continue to work at this plugin. (ReactDom.render is no longer supported in React 18 and Support for defaultProps will be removed)
Cheerio!
Installing the Classic Widget plugins seems to work. Updated WP to the latest version (6.6.2 at this time), and with the Classic Widget, all the sidebars are accessible.
