select_advanced ajax value not saved

Correction
After some research, the value is in database but the select is empty on the backend.

So I found an hack but it's not really sexy.

You can find adaptation here

My "temporary" solution is setting 2 more fields
1 - html field for jquery script
2 - hidden field to option value for select2

When select_advanced field change, hidden field is updated with values of select_advanced
When the page load, we populate select_advanced with the hidden field

You can maybe adapt "select_advanced" to detect when we are in ajax situation and populate with an hidden_field like I did ?

See documentation of Select2

I found a more sexiest solution.

It's a continuation of my reply

Explanations:

I coded a custom field type based on select_advanced (see documentation).

This custom field type named "select_advanced_ajax"

The gist is in two part
1 - Creation of a Meta Box with a custom Class (MetaBoxClass.php)
2 - Our custom field type declaration (RWMB_Select_advanced_ajax_Field.php)

When the field is saved, we add in the database the hidden field.

My code : https://gist.github.com/harkor/2fad09a642a096eb0a48984669211312

I didn't want create a javascript file for that because it's make a third file.

Feel free to adapt.

If the support team have a better solution give it to me 😀