I am afraid an hack is needed for this, but it's not a good idea because an upgrade will override the change.
The link is on manager/frames/menu.php line 241, 242:
// search
$sitemenu[] = '<li><a onclick="this.blur();" href="index.php?a=71" target="main">'.$_lang['search'].'</a></li>';
Edit: maybe it is possible with a plugin, but I am not sure.
[ed. note: microcipcip last edited this post 14 years, 4 months ago.]