How to add custom field to dropdown list?

Question

WordPress

Good afternoon. I have two custom fields telephone_1 and telephone_2 which work great.
But, for some reason, only one telephone_1 field appeared in the drop-down list, and the second one is still not added there

. Tell me, how can I make an arbitrary telephone_2 field be in the drop-down list?

Answer 1

Issue resolved. Business was in restriction of a limit of an output of keys of arbitrary fields.
Decided like this:

add_filter( 'postmeta_form_limit', function( $limit ) {
    return 50;
} );