anchor.diff:          <c:forEach items="${activityTypes}" var="activityType"><option value="${activityType.id}" <c:if test="${selectedActivity.type.id == activityType.id}">selected="selected"</c:if>>${activityType.name}</option></c:forEach>
       </select>
       <select id="add-activity">
  -        <c:forEach items="${activities}" var="activity"><option value="${activity.id}" <c:if test="${selectedActivity.id == activity.id}">selected="selected"</c:if>>${activity.name}</option></c:forEach>
  +        <option>Loading...</option>
       </select>
       <input type="button" id="add-activity-button" value="Add to period"/>
       <a id="newActivityLink" href="<c:url value="/pages/newActivity?returnToPeriodId=${period.id}"/>">Create new activity</a>
  
positive.code:             SC.slideAndShow(rowId)
          }
  
          function showEmptyMessage() {
              if (currentActivityCount() > 0) {
                  SC.slideAndHide('no-activities-message');
  
negative.code:         }
  
          function selectedActivity() {
              return selectedValue('add-activity')
          }
  
          function selectedValue(selectorName) {
              var selector = $(selectorName)
              var selected = selector.options[selector.selectedIndex]
              return {
                  name: selected.text,
  