I prefer this (LESS):
/* Disable link */
a.disabled,
a.disabled:visited ,
a.disabled:active,
a.disabled:hover {
color: #999 ;
cursor: default;
}
.dropdown-menu {
a.disabled,
a.disabled:visited ,
a.disabled:active,
a.disabled:hover {
color: #999 ;
cursor: default;
background-color: white;
}
}