Weirdness with hover and transparent regions

Weirdness with hover and transparent regions

      Hi all, I am new to jQuery and web development in general (not new to development, but thought I would see if this whole interweb thing was a fad or not).  First off, love jQuery, it is the awesome.  That said I am seeing some weirdness in IE 8 (wut?!?  I know!) with jQuery's hover method and wondering if it was a known issue or something I am doing wrong.
 
      I will try to explain what I am seeing, perhaps I can upload pics/attachments if it is unclear.  I have this (more or less)
 
  1. <div>
      <ul>
        <li class="navButton">
            <img src="Image1" Alt="Image1" />
        </li>
     
        <li class="navButton">
            <img src="Image2" Alt="Image2" />
        </li>
     
        <li class="navButton">
            <img src="Image3" Alt="Image3" />
        </li>
     
        <li class="navButton">
            <img src="Image4" Alt="Image4" />
        </li>
      </ul>
    </div>
 
      Now neither this div, unordered list or any list items has a background-color set (so I assume they default to transparent), but they live on an element that does have a solid color background set.  On page load I use $('.navButton').hover(OnHoverEnter,OnHoverLeave) to hook up mouse handlers to each navButton.  So far so good, things get hooked up and called back.  The problem I am seeing seems to be around transparent regions.  Specifically the images have some solid areas and some transparent areas.  I seem to be getting mouse leave events when I hit a transparent area (assuming because the hit pixel 'belongs' to the outermost owning div that has the background set).  If I then move another pixel I get a mouse enter, another pixel a mouse leave.  I don't see this weird behavior while over the solid areas of my images.  I also don't see this behavior if I set the li items to have a background-color in the CSS.  Unfortunately I can't set the background on the li or ul for other reasons.  Is this expected behavior?  Am I doing it wrong?  Thanks for any help, sorry for the long message.
 
Ryan