This is a problem that I found when I was using a superfish drop-down menu with Drupal 7 and Omega, but it is a solution that would work across the board for anybody using a drop-down menu. The primary menu using Drupal is usually in the header-wrapper div (zones-above in Omage) and content is in the main-wrapper div (zones-content in Omage). If you are not using Drupal you probably still have the menu wrapped in the header. So, in your ie7.css, set the header wrapper to have a z-index of 2, and set no z-index on main-wrapper (which means its 1). Now all content in header-wrapper will appear above main-wrapper, no matter if something has z-index:10000000 somewhere in main-wrapper. NOTE: This is only in IE7, and possibly below, but who cares about IE6 anymore. IE8 has thankfully fixed this problem
Nice and simple, hope this helps. Leave a comment if you’ve found this useful.