One of oldest sites on web comes to MODx

.menu ul li a.hide, .menu ul li a:visited.hide {
display:none;
}
.menu ul li a:hover ul li a.hide {
display:none;
}
.menu ul li a:hover {
color:#fff; 
background:#337799;
}
.menu ul li a:hover ul {
display:block; 
position:absolute; 
top:30px; left:0; 
width:144px;
}
.menu ul li a:hover ul li a.sub {
background:#6a3; 
color:#fff;
}
.menu ul li a:hover ul li a {
display:block; 
background:#ddd; 
color:#000;
}
.menu ul li a:hover ul li a ul {
visibility:hidden;     /* keeps third-level flyouts from appearing in main dropdown */
}
.menu ul li a:hover ul li a:hover {
background:#aacccc; 
color:#000;
}
.menu ul li a:hover ul li a:hover ul {
display: block;
visibility:visible; 
position:absolute; 
left:144px; 
top:0; 
color:#000;
}
/* these are mine */

.menu ul li a:hover ul li a:hover ul.left {
left:-144px;
}

.menu ul li.active, .menu ul li.active:hover {    
    color:red;
        background-color:black;    
}

.menu ul li.active a, .menu ul li.active a:hover {
        background-color:black;
    color: red;
}

.menu ul li ul li.active a, .menu ul li ul li.active a:hover {
        background-color:black;
    color: red;

} 

<!--[if lte IE 6]>
  <style type="text/css">
   body {behavior: url(/assets/js/csshover.htc);}
  </style>
<![endif]-->