I'm having an issue with my modalpopupextender.  it works fine in FF and IE7, but in IE6 it goes wonky.  Basically, when someone clicks on a picture (an image control, in my app) it is supposed to invoke the MPE to display a panel with an image and close button.  In IE6, it goes modal, but it displays my hidden modal panel inline with the page under the transparent modal background and does not let me click anything, therefore disallowing the user from any further interaction with the page.  I can't seem to figure out what's wrong.  My code is below:

 <div class="display">

<asp:panel id="pnlActionBlowup" runat="server" cssclass="modal-image" style="display: none;">
<img src="images/blowup-action.jpg" alt="T-Shirt Blowup" />
<p><asp:imagebutton id="btnCloseAction" runat="server" imageurl="images/button-modal-close.gif" /></p>
</asp:panel>

<cc1:modalpopupextender id="mpeAction" runat="server" targetcontrolid="imgbtnAction" popupcontrolid="pnlActionBlowup" backgroundcssclass="modal" cancelcontrolid="btnCloseAction" y="30" />

<asp:imagebutton id="imgbtnAction" runat="server" imageurl="images/shirt-action.gif" alternatetext="ACTION T-Shirt" />
<p>ACTION T-Shirt</p>

</div>