스킨의 list.php 파일을 수정해주세요.

아래 코드 입니다.

<div class="kboard-search">
    <select name="target">
        <option value=""><?php echo __('All', 'kboard')?></option>
        <option value="title"<?php if($_GET['target'] == 'title'):?> selected="selected"<?php endif?>><?php echo __('Title', 'kboard')?></option>
        <option value="content"<?php if($_GET['target'] == 'content'):?> selected="selected"<?php endif?>><?php echo __('Content', 'kboard')?></option>
    </select>
    <input type="text" name="keyword" value="<?php echo $_GET['keyword']?>" placeholder="<?php echo __('Search', 'kboard')?>...">
</div>

아래처럼 수정해주세요.

<div class="kboard-search">
    <select name="target">
        <option value="">전체</option>
        <option value="title"<?php if($_GET['target'] == 'title'):?> selected="selected"<?php endif?>>제목</option>
        <option value="content"<?php if($_GET['target'] == 'content'):?> selected="selected"<?php endif?>>내용</option>
    </select>
    <input type="text" name="keyword" value="<?php echo $_GET['keyword']?>" placeholder="검색...">
</div>