function.phpへの記述

function mvwpform_autop_filter() {
  if (class_exists('MW_WP_Form_Admin')) {
    $mw_wp_form_admin = new MW_WP_Form_Admin();
    $forms = $mw_wp_form_admin->get_forms();
    foreach ($forms as $form) {
      add_filter('mwform_content_wpautop_mw-wp-form-' . $form->ID, '__return_false');
    }
  }
}
mvwpform_autop_filter();