Keep Username As Display Name

/**

 * When people update their profile, keep their display name set to

 * be the same as their login name (username).

 */

function ed_charitable_keep_original_display_name( $values ) {

    $values['display_name'] = wp_get_current_user()->user_login;

    return $values;

}

add_filter( 'charitable_profile_update_values', 'ed_charitable_keep_original_display_name' );

add_filter( 'charitable_campaign_submission_user_data', 'ed_charitable_keep_original_display_name' );