sub navigation disappears

Hi,

See uri: http://http://testing.backstageweb.net/. Mouse over the "home" menu, there is a sub-menu item there. When you mouse over that, it disappears. Suspect code:

Code:

---

.menu#nav-primary {
        background:url(../images/nav_bkgrnd.jpg)no-repeat;
        /*overflow:hidden;*/
        width:1000px;
        height:145px;
        margin:0;
        }

#nav-primary li {
        margin-right: 10px;
        }
       
#nav-primary a, #nav-primary a:visited  {
        background-color:transparent;
        padding:7px 16px;
        color:#fff;
        display:block;
        }

#nav-primary a:hover, #nav-primary a:active {
        background-color:transparent;
        color:yellow;
        outline:0;
        }

---

Any help is appreciated.

John