Read the entire thread on wordpress.org.
add_action( 'restrict_manage_posts', 'my_restrict_manage_posts' );
function my_restrict_manage_posts() {
global $typenow;
$taxonomy = $typenow.'_type';
if( $typenow != "page" && $typenow != "post" ) {
$filters = array($taxonomy);
foreach ($filters as $tax_slug) {
$tax_obj = get_taxonomy($tax_slug);
$tax_name = $tax_obj->labels->name;
$terms = get_terms($tax_slug);
echo '<select id="$tax_slug" class="postform" name="$tax_slug" data-ddg-inputtype="unknown">';
echo '<option value="">Show All $tax_name</option>';
foreach ($terms as $term) {
echo '<option selected="selected" value=". $term->slug, $_GET[$tax_slug] == $term->slug ? ">'.$term->name.' ('.$term->count.')</option>';
}
echo "</select>";
}
}
}
Reference Links
https://wordpress.org/support/topic/show-categories-filter-on-custom-post-type-list/
