.dropdown-submenu {
    position: relative;
}

.dropdown-submenu>.dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px;
     border-radius: 0 6px 6px 6px;
   
}


/* display:block server per far spuntare il sottomenu  */
.dropdown-submenu:hover>.dropdown-menu {
   display: block;

}

/* il blocco successivo serve per definire la selezione sul passaggio del mouse */
.dropdown-menu>li>a:hover, .dropdown-menu>li>a:focus
{
    color: #fff;
    text-decoration: none;
   /* font-style: italic;
    font-weight: bold; */
   /* font-size: 150%; */
    background-color: #428bca;
}


.dropdown-submenu>a:after {
    display: block;
    content: " ";
    float: right;
    width: 0;
    height: 0;
    border-color: transparent;
    border-style: solid;
    border-width: 5px 0 5px 5px;
    border-left-color: #ccc;
    margin-top: 5px;
    margin-right: -10px;
    
}

.dropdown-submenu:hover>a:after {
    border-left-color: #fff;
    
}

.dropdown-submenu.pull-left {
    float: none;
}

.dropdown-submenu.pull-left>.dropdown-menu {
    left: -100%;
    margin-left: 10px;
    -webkit-border-radius: 6px 0 6px 6px;
    -moz-border-radius: 6px 0 6px 6px;
    border-radius: 6px 0 6px 6px;
}