wp_editor() does not work in the meta box area

[rilwis]

Issue Overview

In the meta box area, if we use a custom field that renders an old editor via wp_editor(), then that editor is broken. I understand that Gutenberg removes all the instances of TinyMCE, but the core PHP function wp_editor() should work as expected.

The TinyMCE editor is quite important for users. They need more "areas" to enter extra content, not just in the main editor, which can be outputted in different locations in the frontend.

Steps to Reproduce (for bugs)

I tested with my plugin Meta Box, but I guess it happens with any code that uses wp_editor().

To reproduce the bug, please install the Meta Box plugin. Then put the following code into functions.php of the active theme:

add_filter( 'rwmb_meta_boxes', function( $meta_boxes ) {
    $meta_boxes[] = [
        'title' => 'Test file upload',
        'fields' => [
            [
                'id' => 'my_custom_editor',
                'type' => 'wysiwyg',
                'name' => 'Test editor',
            ]
        ],
    ];
} );

Then go to add a new post and see how it works.

Any solution is appreciated! Thanks for your time and hard work!

[chthonic-ds]

Related #3302

[youknowriad]

I'm closing this as duplicate of #3302 There's a PR that might land in the future fixing this #3840