Flyout shopping cart hidden behind content_before slider in IE9

I've implemented NOP Anywhere Sliders on NOP 2.6.  Everything works great EXCEPT in IE9, which hides the flyout shopping cart behind the Slider that I've placed in the content_before area.  I'm using a modified theme, but the same thing happens with the Dark Orange theme.  Chrome and Firefox are fine, it's just IE that's a problem.  Can you advise on how to resolve this?  (see www.shop.camperserv.com to see the problem)

Thanks

Hi camperserv,

We tested on your web site and our demo site with IE9 and we couldn't reproduce this problem.
Could you please check if you are running your IE with Compatibility Mode?
Please note that older IE browsers i.e IE6 and IE7 don't support z-index.

Thanks

Hi. You're right, compatibility mode wasn't switched on (because I generally don't use IE). The only thing is, there's no way to know what settings a customer might have.  I guess the only option is to include a "Problems Viewing This Site?" section.  Thanks