Hi mrv,
Check out the code below and test it out.
add_filter('geodir_detail_page_tab_list_extend', 'geodir_detail_page_tab_list_extend') ;
function geodir_detail_page_tab_list_extend($tab_array) {
$tab_array['my_new_tab'] = array(
'heading_text' => __('New Tab',GEODIRECTORY_TEXTDOMAIN),
'is_active_tab' => false,
'is_display' => apply_filters('geodir_detail_page_tab_is_display', true,'my_new_tab'),
'tab_content' => '');
$tab_array['my_new_tab2'] = array(
'heading_text' => __('New Tab2',GEODIRECTORY_TEXTDOMAIN),
'is_active_tab' => false,
'is_display' => apply_filters('geodir_detail_page_tab_is_display', true,'my_new_tab2'),
'tab_content' => '');
$tab_array['my_new_tab3'] = array(
'heading_text' => __('New Tab3',GEODIRECTORY_TEXTDOMAIN),
'is_active_tab' => false,
'is_display' => apply_filters('geodir_detail_page_tab_is_display', true,'my_new_tab3'),
'tab_content' => '');
return $tab_array ; }