/**
  * Private function called once at the beginning of each ConceptSearchResultsGroup
  */
 protected function _group_header(ConceptSearchResultsGroup $csrg, $group_i)
 {
     // Determine whether group starts expanded or collapsed
     $group_num_results = $csrg->getCount();
     if ($this->cc->getSearchResultsGroupCount() == 1) {
         $tbody_style = 'display:table-row-group;';
         $toggle_image = 'images/box_minus.jpg';
     } else {
         $tbody_style = 'display:none;';
         $toggle_image = 'images/box_plus.jpg';
     }
     // Group header
     echo "\n<thead id=\"csrg_header_" . $group_i . "\">";
     echo "<tr class=\"row_group_header\">";
     echo '<th colspan="' . $this->num_columns . '" onclick="javascript:toggleSearchGroup(' . $group_i . ')">';
     if ($this->show_checkbox) {
         echo '<input type="checkbox" id="csrg_checkbox_' . $group_i . '" onclick="csrgCheckboxClick(event, this);"';
         if (!$csrg->getCount()) {
             echo ' disabled="disabled"';
         }
         echo ' />&nbsp;&nbsp;';
     }
     echo '<img id="img_group_toggle_' . $group_i . '" src="' . $toggle_image . '" border="0" alt="Toggle" />&nbsp;&nbsp;';
     echo 'Search Group ' . ($group_i + 1) . ':&nbsp;&nbsp;<span style="font-weight:normal;">' . substr($csrg->csg->query, 0, $this->csrg_text_cutoff_length);
     if (strlen($csrg->csg->query) > $this->csrg_text_cutoff_length) {
         echo '...';
     }
     echo '</span>&nbsp;&nbsp;';
     echo '<span style="font-weight:bold;float:right;">' . $group_num_results;
     echo ' result';
     if ($group_num_results > 1) {
         echo 's';
     }
     echo "</span></th></tr>";
     echo "</thead>\n";
     // Concept column headers
     echo "<tbody id=\"csrg_" . $group_i . "\" class=\"tbody_group\" style=\"" . $tbody_style . "\">\n";
     echo "<tr id=\"csrg_header_row_" . $group_i . "\" class=\"row_table_header\">";
     if ($this->show_checkbox) {
         echo '<th class="col_check"></th>';
     }
     echo "<th class=\"col_1\">Concept</th>";
     echo "<th class=\"col_2\">Definitions</th>";
     echo "<th class=\"col_3\">Concept Sets</th>";
     echo "<th class=\"col_4\">Mappings</th>";
     if ($this->show_icons) {
         echo '<th class="col_icons"></th>';
     }
     echo "</tr>\n";
 }