Search issues

Bug: if you search on this blog, it only searches within the currently active ‘group’, whether that’s a category, day or post, or the whole blog. The code in question is:

    <form id="searchform" method="post" action="{$Smarty.server.PHP_SELF}">
        <div style="text-align:center">
            <p><input type="text" name="s" id="s" size="20" /></p>
            <p><input type="image" src="/images/search.png" name="submit" value="Search" /></p>
        </div>
    </form>

Obviously, the important part is the {$Smarty.server.PHP_SELF} section. Setting it to {$Smarty.server.SERVER_NAME} or several other things seems to make no difference!