li.showsensor
{
   font-weight: bold;
}
li.showsensor ul.hiddenlist
{
   visibility: hidden;
   display: none;
}
li.showsensor:hover ul.hiddenlist
{
   display: inline;
   visibility: visible;
   font-weight: normal;
}
ul.hiddenlist:hover
{
  display: inline;
  visibility: visible;
}