remove subcategories from pull down menu in search_header

[Jerry5763837]

hi, everyone,

i don't know if i'm at the right place to rising this question.

i came across the problem as stated as above topic title.
that is: in advanced search page, when click the category pull down menu, it includes master categories & subcategoies.
therefore, how to remove subcategoies from the pull down menu?

here is the code

<?php echo zen_draw_pull_down_menu('categories_id', zen_get_categories(array(array('id' => '', 'text' => TEXT_ALL_CATEGORIES)), '0' ,'', '1'), $sData['categories_id']); ?>
<?php require(DIR_WS_MODULES . 'sideboxes/search_header.php'); ?>

Many appreciated for your suggestion.