Nee, de forumcode is daar vrij simpel in. Zoek je vanuit een topic of board, dan wordt de ID van dat topic of board meegestuurd in je zoekvraag. En dan zoek je dus alleen binnen een beperkt gedeelte van het forum.
<div class="search">
<form id="search_form" action="', $scripturl, '?action=search2" method="post" accept-charset="', $context['character_set'], '">
<input type="text" name="search" value="" class="input_text" />
<input type="submit" name="submit" value="', $txt['search'], '" class="button_submit" />
<input type="hidden" name="advanced" value="0" />';
// Search within current topic?
if (!empty($context['current_topic']))
echo '
<input type="hidden" name="topic" value="', $context['current_topic'], '" />';
// If we're on a certain board, limit it to this board ;).
elseif (!empty($context['current_board']))
echo '
<input type="hidden" name="brd[', $context['current_board'], ']" value="', $context['current_board'], '" />';
echo '</form>
</div>