anchor.diff:  .palette div#delete-drop.hover {
       background-color: #f99;
       cursor: pointer;
  +}
  +
  +.counter.hover {
  +    background-color: #f99;
   }
   
   .palette .tip {
  
positive.code:                     accept: ['marker', 'new-marker'],
                      hoverclass: 'hover',
                      onDrop: moveMarker })
              }
              );
  
  
negative.code:             executeUpdateDetails(input)
          })
      })
  
      $$('.counter').each(function(input) {
          input.observe("click", function() {
              var spanElt = input.getElementsByClassName('marker')[0].innerHTML.toString()
              var inputElt = input.select("input")[0]
              var spanValue = spanElt.replace(/\s/g, "")
              if (spanValue.empty()) {
                  executePlannedActivityAdd(inputElt.id, null)
                  input.select(".marker")[0].innerHTML = 'X';
              }
          });
  
          input.observe('mouseover', function(){
              input.addClassName('hover')
          });
  
          input.observe('mouseout', function(){
              input.removeClassName('hover')
          });
      })
  
  }
  
  function updateAddActivityButton() {
  