Custom Field not saving in Wordpress

Question

before I start, I am not using any plugins for my CPT and Custom Fields. I do not want to make use of such plugins.

I am using several Custom Post Types and also include Custom Fields within the posts created. For some odd reason the Custom Fields created under Videos will not be saved. Everytime I have to create a new custom field with the same name and have to add the content again. I cannot pick the respective custom fields in that dropdown list.

The Custom Field and it's content are stored in the Wordpress Data base but Wordpress "forgets" them when I create a new Custom Post.

I created the CPT as follows:

// Video Custom Post Type
function video_init() {
    // set up product labels
    $labels = array(
        'name' => 'Videos',
        'singular_name' => 'Video',
        'add_new' => 'Add New Video',
        'add_new_item' => 'Add New Video',
        'edit_item' => 'Edit Video',
        'new_item' => 'New Video',
        'all_items' => 'All Videos',
        'view_item' => 'View Video',
        'search_items' => 'Search Videos',
        'not_found' =>  'No Videos Found',
        'not_found_in_trash' => 'No Videos found in Trash', 
        'parent_item_colon' => '',
        'menu_name' => 'Video',
    );

    // register post type
    $args = array(
        'labels' => $labels,
        'public' => true,
        'has_archive' => true,
        'show_ui' => true,
        'capability_type' => 'post',
        'hierarchical' => false,
        'rewrite' => array('slug' => 'video'),
        'query_var' => true,
        'menu_icon' => 'dashicons-video-alt3',
        'supports' => array(
            'title',
            'editor',
            'custom-fields',
        )
    );
    register_post_type( 'video', $args );

    // register taxonomy
    register_taxonomy('video_category', 'video', array('hierarchical' => true, 'label' => 'Category', 'query_var' => true, 'rewrite' => array( 'slug' => 'video-category' )));
}
add_action( 'init', 'video_init' );
?>

Then I am including youtubelink and subtitle into my post

At the end I am calling the CPT including it's post meta as follows

<!--VIDEOS-->
    <div id="videos" class="block relative" style="z-index: 90;padding-top: 100px;padding-bottom: 100px; margin-top: 50% !important;">
        <h3 class="block">v/deos > </h3>
        <?php $query = new WP_Query( array( 'post_type' => 'video' ) ); ?>
        <?php 

                    $i = 1;
                    ?>
        <?php if ( $query->have_posts() ) : ?>
        <?php while ( $query->have_posts() ) : $query->the_post(); ?>
        <?php if(($i % 2) == 0) { ?>
        <div class="full-width text-left big-big-block video-cnt">
            <div class="row">
                <div class="col-sm-8" style="width: 100%; height: 100% auto">
                    <?php if (!((get_post_meta($post->ID, 'youtubelink', TRUE))=='')) {
                                        echo wp_oembed_get( get_post_meta($post->ID, "youtubelink", true) );
                                        }?>
                </div>
            </div>
            <div class="row">
                <div class="col-sm-5 col-sm-offset-7 text-left video-description-text">
                    <h3>
                        <?php the_title(); ?><br/>
                        <small><?php echo get_post_meta($post->ID, 'subtitle', true); ?> //////////////////</small></h3>
                    <div class="block">
                        <p>
                            <?php the_content(); ?>
                        </p>
                    </div>
                </div>
            </div>
        </div>

        <?php } elseif (($i % 2) !== 0) { ?>
        <div class="full-width text-left big-big-block video-cnt">
            <div class="row">
                <div class="col-sm-8 col-sm-offset-4">
                    <?php if (!((add_post_meta($post->ID, 'youtubelink', TRUE))=='')) {
                                        echo wp_oembed_get( get_post_meta($post->ID, "youtubelink", true) );
                                        }?>
                </div>
            </div>
            <div class="row">
                <div class="col-sm-5 text-right video-description-text">
                    <h3>
                        <?php the_title(); ?><br/>
                        <small><?php echo add_post_meta($post->ID, 'subtitle', true); ?> //////////////////</small></h3>
                    <div class="block">
                        <p>
                            <?php the_content(); ?>
                        </p>
                    </div>
                </div>
            </div>
            <?php } ?>
            <?php $i++; ?>
            <?php endwhile; ?>
            <?php endif; ?>
            <!-- show 404 error here -->
        </div>
    </div>

So now, the moment I create a new Video CPT I have to create the youtubelink and subtitle again. This is frustrating me as everything works perfect its just that under this specific CPT I cannot figure out why I have to create the metafields over and over again.

Answer 1

The post meta form is limited to displaying 30 keys by default. To change the value, use the postmeta_form_limit filter:

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

Also consider adding a custom meta box, where you can set up dedicated fields instead of having to select a key each time.