Meta Box

Ok understood, thanks

thanks it's working and very simple, my problem is solved.

I noticed however that to add innerblocks i have:
1: create at least 1 custom field in the block group
2: custom field created must be not be empty
3: i have to be in preview mode
otherwise in gutenberg backend i see notice: Click the Edit icon in the block toolbar to enter content.
(Added screenshot to explain better): https://imgur.com/a/V6oRzW5

There is a way to add innerblocks without this requirements? (i'm trying to create a container for other custom blocks)

Hi Long,
I would like to insert custom html between metabox custom fields on frontend submission, i guessed i have to use php, but if it's possible in another way it's ok for me.

Hi Long,
coud you post a simple example to get (in backend) block unique id using hook "enqueue_block_editor_assets"? (for example log it to console)

In documentation (https://docs.metabox.io/extensions/mb-blocks/) is mentioned to decode json string but not very clear about how to do it.

Thanks