Meta Box

Hello,

If you don't want to use custom code, please try to use the solution MB Favorite Posts
https://metabox.io/plugins/mb-favorite-posts/

and read more about this plugin in the documentation https://docs.metabox.io/extensions/mb-favorite-posts/

Hello,

In the builder, you can use the dot notation or JSON notation to pass an array to query args. Read more in the documentation https://docs.metabox.io/extensions/meta-box-builder/#dot-notation

Hello,

MB Builder will use a parser to convert settings in JSON files to a field group and save it as a post type, not with just the WordPress function wp_insert_post().

Hello,

Yes, using the filter rwmb_subfieldID_wrapper_html or custom_html field, you need to add the close tags for all open tags. Only the field settings before and after can support your case.

Hello,

If this code

add_action( 'rwmb_frontend_after_process', function( $config, $post_id ) {
    MB_Relationships_API::add( 123, 456, 'projects_to_updates' );
}, 10, 2 );

still does not work, please try to deactivate all plugins except Meta Box, MB extension plugins and switch to a standard theme of WordPress then check this issue again.

Hello,

Can you please check the option "Save field value" of all fields in the field group? I see it is disabled in your screen record and you only enable it for one field "Referent FS".

Hello,

I think you can try a few things below:

2b. Change 'publicly_queryable' => true

5b. Change the shortcode to this
[mb_frontend_form ajax="true" id="update-fields-group" post_fields="title" post_type="update"]

If it still does not work, please add some existing IDs to the code and see if the relationship is created

add_action( 'rwmb_frontend_after_process', function( $config, $post_id ) {
    MB_Relationships_API::add( 123, 456, 'projects_to_updates' );
}, 10, 2 );

where 123 is a project post ID, 456 is a update post ID.

Hello,

Currently, MB Builder does not support auto-import JSON files. You need to import them manually to your site.