Can't see dropdown list items on web page

Question

On my website you can click on "SEARCH" at the top, which will show a dropdown menu. The first list item is visible, but the rest of them are invisible (just click on search and you will see what I mean). How can I make them all visible?

PS: I have tried things like removing overflow:hidden and adding z-index to it, but it didn't work.

The dropdown list's snippet:

echo "
if ($verified_user) {

<span class=\"dropdown dropdown-processed\">
<a class=\"toggles\" href=\"#\">SEARCH</a>
  <div class=\"dropdown-container\" style=\"display: none;\">
<ul class=\"dropdown-menu toggles-menu open\" style=\"list-style-type: none;\">
<li class=\"dropdown\">
<li class=\"nick\">
<a title=\"username\" href=\"/someone/username\">username</a>
</li>
<li>
<a href=\"blabla">lanp</a>
</li>
<li>
<a href=\"blabla">preferences</a>
</li>
<li>
<a href=\"blabla\">subs</a>
</li>
<li class=\"seperated\">
<a href="blabla">log out</a>
</li>
</ul>
</li>
</ul>
</div>
</div>

"; }

It is only visible for registered (and logged in) users, so I echoed it. It is visible indeed, but not the whole list and that is very annoying.

Edit: it looks like the frameset is the problem. How can I solve that issue? This is the frameset: <frameset id="f" border="0" rows="50,*">