[davidw]

You should have

$template_hook[navbar_search_menu]

in your navbar, if you don't - this will not work.

Search for

<!-- / header quick search form -->

and look a couple rows above:

        	$template_hook[navbar_search_menu]
		</table>
	</div>
	<!-- / header quick search form -->

Your navbar may differ a little - this is where the hook resides:

		<tr>
			<td class="vbmenu_option"><a href="search.php$session[sessionurl_q]" accesskey="4" rel="nofollow">$vbphrase[advanced_search]</a></td>
		</tr>
        	$template_hook[navbar_search_menu]

If you do not have that hook in there, you must edit your navbar and place that hook in there to use this modification. If you still can't get this version to work, here is a manual but limited version - https://vborg.vbsupport.ru/showthread.php?t=128274