$this->lfGetCatTree($this->category_id, true, $this);

    // カテゴリツリーの取得
    function lfGetCatTree($arrParent_category_id, $count_check = false) {
        $objQuery = new SC_Query();
        $objDb = new SC_Helper_DB_Ex();
        $col = "*";
        $from = "dtb_category left join dtb_category_total_count using (category_id)";
        // 登録商品数のチェック
        if($count_check) {
            $where = "del_flg = 0 AND product_count > 0";
        } else {
            $where = "del_flg = 0";
        }
        $objQuery->setOption("ORDER BY rank DESC");
        $arrRet = $objQuery->select($col, $from, $where);

        foreach ($arrParent_category_id as $category_id) {
            $arrParentID = $objDb->sfGetParents($objQuery, 'dtb_category', 'parent_category_id', 'category_id', $category_id);
            $arrBrothersID = SC_Utils_Ex::sfGetBrothersArray($arrRet, 'parent_category_id', 'category_id', $arrParentID);
            $arrChildrenID = SC_Utils_Ex::sfGetUnderChildrenArray($arrRet, 'parent_category_id', 'category_id', $category_id);

            $this->root_parent_id[] = $arrParentID[0];

            $arrDispID = array_merge($arrBrothersID, $arrChildrenID);

            foreach($arrRet as $key => $array) {
                foreach($arrDispID as $val) {
                    if($array['category_id'] == $val) {
                        $arrRet[$key]['display'] = 1;
                        break;
                    }
                }
            }
        }

        $this->arrTree = $arrRet;
    }

<style type="text/css">
select option.level1 { background-color:#999; color:#fff; }
select option.level2 { background-color:#f6f6f6; }
select option.level3 { background-color:#ff0000; }
select option.level4 { background-color:#00ff00; }
select option.level5 { background-color:#0000ff; }
</style>

<!--{section name=cnt loop=$arrTree}-->
<option label="<!--{$arrTree[cnt].category_name}-->" value="<!--{$arrTree[cnt].category_id}-->" class="level<!--{$arrTree[cnt].level}-->"<!--{if $smarty.get.category_id == $arrTree[cnt].category_id}--> selected<!--{/if}-->><!--{$arrTree[cnt].category_name}--></option>
<!--{/section}-->