API page: http://api.drupal.org/api/drupal/includes%21theme.inc/function/theme_tab...
I have changed a piece code in tablesort.inc file and it worked correctly. please consider
In dunction tablesort_header$cell['data'] = l($cell['data'] . $image, $_GET['q'], array('attributes' => array('title' => $title), 'query' => array_merge($ts['query'], array('sort' => $ts['sort'], 'order' => $cell['data'])), 'html' => TRUE));
replace by$cell['data'] = l($cell['data'] . $image, $_GET['q'], array('attributes' => array('title' => $title), 'query' => array_merge($ts['query'], array('sort' => $ts['sort'], 'order' => $cell['field'])), 'html' => TRUE));
and in function tablesort_get_order
$order = isset($_GET['order']) ? $_GET['order'] : '';
replace by
if(isset($_GET['order'])) {
foreach($headers as $header)
if($_GET['order'] == $header['field'])
$order = $header['data'];
} else
$order = '';