Custom taxonomy not showing terms in post area

Seems like its creating some conflict. Can you try with this code ?

add_action( 'init', 'country_init' );

function country_init() {

    $labels = array( 
        'name' => _x( 'Countries', 'countries' ),
        'singular_name' => _x( 'Country', 'countries' ),
        'search_items' => _x( 'Search Countries', 'countries' ),
        'popular_items' => _x( 'Popular Countries', 'countries' ),
        'all_items' => _x( 'All Countries', 'countries' ),
        'parent_item' => _x( 'Parent Country', 'countries' ),
        'parent_item_colon' => _x( 'Parent Country:', 'countries' ),
        'edit_item' => _x( 'Edit Country', 'countries' ),
        'update_item' => _x( 'Update Country', 'countries' ),
        'add_new_item' => _x( 'Add New Country', 'countries' ),
        'new_item_name' => _x( 'New Country', 'countries' ),
        'separate_items_with_commas' => _x( 'Separate countries with commas', 'countries' ),
        'add_or_remove_items' => _x( 'Add or remove countries', 'countries' ),
        'choose_from_most_used' => _x( 'Choose from the most used countries', 'countries' ),
        'menu_name' => _x( 'Countries', 'countries' ),
    );

    $args = array( 
        'labels' => $labels,
        'public' => true,
        'show_in_nav_menus' => true,
        'show_ui' => true,
        'show_tagcloud' => true,
        'show_admin_column' => false,
        'hierarchical' => true,

        'rewrite' => true,
        'query_var' => true
    );

    register_taxonomy( 'countries', array('post'), $args );
}