add_new_post_status.php

<?php

// Registering custom post status
function dom_custom_post_status() {
    register_post_status( 'block', array(
        'label'                     => _x( 'Blocked', 'post' ),
        'public'                    => false,
        'exclude_from_search'       => false,
        'show_in_admin_all_list'    => true,
        'show_in_admin_status_list' => true,
        'show_in_metabox_dropdown'  => true,
        'show_in_inline_dropdown'   => true,
        'date_floating'   => true,
        'post_type'                 => array( 'w2dc_listing' ),
        'label_count'               => _n_noop( 'Blocked <span class="count">(%s)</span>', 'Blocked <span class="count">(%s)</span>' ),
    ) );
}
add_action( 'init', 'dom_custom_post_status' );

// Using jQuery to add it to post status dropdown
add_action( 'admin_print_footer_scripts', 'dom_append_post_status_list' );
// add_action( 'admin_print_scripts-post-new.php', 'dom_append_post_status_list' );
function dom_append_post_status_list() {
    global $post;
    $complete = '';
    $label    = '';
    if ( $post->post_type == 'w2dc_listing' ) {
        if ( $post->post_status == 'block' ) {
            $complete = ' selected="selected"';
            $label    = '<span id="post-status-display"> Blocked</span>';
        }
        echo '
<script>
    jQuery(document).ready(function($){
        $("select#post_status").append("<option value=\"block\" ' . $complete . '>Blocked</option>");
        $(".misc-pub-section label").append("' . $label . '");
    });
</script>';
    }
}