Links from 2nd vertical menu appear in submenu of 1st vertical menu

Question

http://www.westhoustonairport.com/index_troubleshoot.shtml - Problem occurs in IE
I have five vertical Spry menus.  Some of the menus have submenus.  Go to PHOTO COLLECTION first, and the submenu looks good.  Then go to either HANGARS / OFFICES or HISTORY in the third vertical menu, and you'll see that the submenus contain links from the fourth vertical menu.
As a temporary fix, I switched PHOTO COLLECTION (which has a submenu) with ON-AIRPORT BUSINESSES (no submenu), which you can see here:
http://www.westhoustonairport.com.  There is no problem now because the fourth column no longer contains links with submenus.
I, however, need to change the links back to the previous order.  What is causing the links to appear in the previous column's submenu?  Thank you.

Answer 1

The following is where you should specify the menu items background color
ul.MenuBarVertical a
     display: block;
     cursor: pointer;
     /*background-color: #000ECE;*/
     padding: 0.5em 0.95em;
     /*color: #333;*/
     color: #FFF;
     text-decoration: none;
The browser and I do not understand the following style rule
ul.MenuBarVertical a.MenuBarItemSubmenu
     /*background-image: url(SpryMenuBarRight.gif);*/
     background-image: url(SpryMenuBarRightHover.gif);
     background-repeat: no-repeat;
     background-position: 95% 50%;
     display:!important;
Gramps