Chronic Bounce - Mouseenter Mouseleave

Chronic Bounce - Mouseenter Mouseleave

Symptoms:
In FF and maybe other browsers, I have a weird bug.
When you slowly move mouse up and then just past the top of the search tab you can get the animation into a 'BOUNCE' state. Up and down, Up and down. I want to eliminate this bug like behavior but I can't seem to figure out how. Do you have any ideas or possible work-arounds? I would appreciate it so much!


Live code here:

http://www.architecture2030.org/temp/re ... 90409.html

JQUERY code:
<script type="text/javascript">

$(document).ready(function(){
   $("#searchtab").mouseenter(function(){
      document.getElementById('searchform').className = "show";
        $("#searchtab").animate({
        height: "150px"
      }, 'normal', null, function() { document.getElementById('searchform').className = "show"; }  );
    }).mouseleave(function(){
         $("#searchtab").animate({
        height: "40px"
      }, 'normal', null, function() { document.getElementById('searchform').className = "hide"; } )
      });
});

</script>


HTML code:

<div id="searchtab"><br />search 2030 (most popular and more)
    <div id="searchform" class="hide"><br /><br /><input type="text" name="kw" />&nbsp;&nbsp;<input type="button" value="search" />
    </div>
</div>


CSS code:
#searchtab {
   font-family: Helvetica, Arial, sans-serif;
   font-size: 15px;
   color: #000000;
   background-color: transparent;
  background-repeat: repeat-x;
   height: 40px;
   width: 300px;
   position: absolute;
   z-index: 32;
   background-image: url(images/searchtab_full.png);
   text-align: center;
   line-height: 95%;
   bottom: 0px;
   right: 240px;
}
#searchform {
   background-color: transparent;
  background-repeat: repeat-y;
  height:60px;
  position:relative;
  top:11px;
}