Now I'm getting the same behavior in FireFox 1.5 on the horizontal menu. A dotted white rectangular box around the entire menu when a item is selected.  Here is my code.  Any help solving this problem would be greatly appreciated.

/* =======================
 Horizontal Nav Menu
 =======================*/

.main_dnnmenu_bar
{
    cursor: auto;
    background-color: Transparent;
   
}

.main_dnnmenu_item
{
    cursor: auto;
    background-color: Transparent; 
}

.main_dnnmenu_rootitem
{
    cursor: auto;
    color: #f5f5f5;
    font-size: 12px;
    font-weight: bold;
    font-style: normal;
    background-color: Transparent;
    font-family: Georgia, Tahoma, Arial, Helvetica, sans-serif;
    padding: 0px 28px 0px 0px;
    margin-left: 15px;
}

.main_dnnmenu_itemhover
{
   
    color: #b30401;
   
}

.main_dnnmenu_itemselect
{
    color: #b30401;
}

/* =======================
 Verticle SubNav Menu
 =======================*/

.main_subdnnmenu_bar
{
    cursor: auto;
    line-height: 40px;
    background-color: Transparent;
}

.main_subdnnmenu_container
{
    cursor: auto;
    background-color: Transparent;
}

.main_subdnnmenu_item
{
    cursor: auto;
    background-color: Transparent;
}

.main_subdnnmenu_rootitem
{
    cursor: auto;
    color: #4c4533;
    font-size: 12px;
    font-weight: bold;
    background-color: Transparent;
    font-family: Georgia, Tahoma, Arial, Helvetica, sans-serif;
    padding: 0px 0px 0px 0px;
    margin-left: 25px;
}

.main_subdnnmenu_itemhover
{
   
    color: #b30401;
}

.main_subdnnmenu_itemselect
{
    color: #b30401;
}
 

unfortunately no...I've been consumed with the skin and have not migrated from my dev server to production.  By mentioning hack, I assume you have seen this problem referenced elsewhere?  I'll start googling.  Strange thing is, it is now happening in FF 1.5 and it wasn't happening before.  Opera displays fine.