Your problems are probably related to the fact that you have built your html incorrectly. The submenu ( .level-two) should be nested in the elements .level-one li:
<div id="navtree">
<ul class="level-one">
<li><a href="/about/" title="about">about</a></li>
<li><a href="/contact/" title="contact">contact</a></li>
<li><a href="/feeds/latest/" title="subscribe">subscribe</a></li>
<li><a href="/Test1/" title="Test1page">Test1</a>
<ul class="level-two">
<li><a href="/Test1/testsub/" title="test1subpage">Test1sub</a></li>
</ul>
</li>
<li><a href="/Test2/" title="Test2 page">Test2</a>
<ul class="level-two">
<li><a href="/Test2/subpage2/" title="Testsubpage2">Testsubpage2</a></li>
</ul></li>
</ul>
</div>
css:
.level-one {display: inline; position: relative; }
.level-one {display: none; position: absolute; left: 0; top: 1em; }
.level-one:hover .level-two {display: block; }
, , . .
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