my problem with the submenu...(lets see if i can describe this properly)

when i first open a submenu all the underlines under every link is there as i coded it in css, but once i mouse over it disappears and it stays disappeared. i open the submenu again and the underlines are still gone. unless i refresh the page it will stay gone

heres my code if it helps:

/* Applies to idle state of submenu items */
.MainMenu_MenuItem
{
    font-family: arial;
    font-size: 12px;
    font-weight: normal;
    cursor: hand;
    color: #000;
    background: #00AEDB;
    border-top: 1px solid #00AEDB;
    border-left: 1px solid #00AEDB;
    border-right: 1px solid #00AEDB;
    border-bottom: 1px solid #000;
    padding: 0px 14px 0px 6px;
    width: 130px;
}

/* Hover state for submenu items */
.MainMenu_MenuItemSel
{
    font-family: arial;
    font-size: 12px;
    font-weight: normal;
    cursor: hand;
    color: #fff;
    background: #000;
    border-top: 1px solid #00AEDB;
    border-left: 1px solid #00AEDB;
    border-right: 1px solid #00AEDB;
    border-bottom: 1px solid #000;
    padding: 0px 14px 0px 6px;
    width: 130px;
}

before:

after: