[jQuery] Can anyone explain the jitter in my website using the "slide" effect?

[Eric]

I am building a website and using the "slide" effect to transition
objects in and out of the screen.  For some reason, in Firefox 3, the
"slide" effect using {direction: "down"} creates a weird jitter at the
bottom of the div that is sliding down.  The website to see is
www.freewebs.com/edauenhauer.  Click on one of the songs on the side
and then click on any other song or on the "close" button.  The jitter
occurs at the bottom of the screen when it closes.

Here is the jQuery code I'm using.  Functionally, it works fine, but I
want to try to solve this aesthetic glitch.

   $('a.title').each(function(index) {
     $(this).click(function() {
       $('div.content:visible').hide("slide", {direction: "down"},
500).end()
         $('div.content').eq(index).slideDown(500);
       return false;
     });
   });


Oddly enough, it works fine in IE 7 (it also works in IE 6).  Firefox,
however, is my browser of choice and I was hoping there was a way to
get it to render correctly.  Thanks for any help.