Can't get it to work also. No Popup in IE7/IE8 (navbar or $lsaform)
vBulletin 3.8.1pl1 (using Standard-Style without any edits (only navbar

)).
PHP: 5.2.6
MySQL Version: 5.0.67-community (Charset: UTF-8 Unicode (utf8))
This is the only change i did in template navbar:
Code:
<form action="search.php?do=process" method="post">
<div id="lsa_window">
<input type="hidden" name="do" value="process" />
<input type="hidden" name="quicksearch" value="1" />
<input type="hidden" name="childforums" value="1" />
<input type="hidden" name="exactname" value="1" />
<input type="hidden" name="s" value="$session[sessionhash]" />
<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" />
<div>
<input type="text" class="bginput" size="25" id="lsa_input" name="query" tabindex="1001" maxlength="$vboptions[lsa_maxsym]" value="$vbphrase[live_search]" <if condition="!in_array($bbuserinfo[usergroupid], array($vboptions[lsa_group]))">onfocus="vbmenu_register('lsa_window',1); if(this.value=='$vbphrase[live_search]'){this.value=''}; showHint();" onblur="this.value='$vbphrase[live_search]';" onkeyup="showHint();"<else />onfocus="if(this.value=='$vbphrase[live_search]'){this.value=''};" onblur="this.value='$vbphrase[live_search]';"</if> />
<input type="submit" class="button" value="$vbphrase[go]" tabindex="1004" />
</div>
<div style="margin-top:$stylevar[cellpadding]px">
<label for="rb_nb_sp0"><input type="radio" name="showposts" value="0" id="rb_nb_sp0" tabindex="1002" checked="checked" />$vbphrase[show_threads]</label>
<label for="rb_nb_sp1"><input type="radio" name="showposts" value="1" id="rb_nb_sp1" tabindex="1003" />$vbphrase[show_posts]</label>
</div>
</div>
</form>
With Firefox and Chrome the code in navbar is not working fine, because I've no chance to enter any word.
With $lsaform placed in header or FORUMHOME for example, your hack is working fine, but not with IE7/IE8 at the moment
Video:
http://ioj.com/v/3pvf5
Regards, Stoebi