anchor.diff:      var siblings = $$('div.epoch')
   
       updateMoveControlVisibility('epoch', thisEpoch.id.split('-')[1], thisEpoch, siblings)
  -    updateDeleteControlVisibility('epoch', siblings)
  +    updateDeleteControlVisibility('epoch', siblings, 'epochs')
   }
   
   function updateAllEpochsControlVisibility() {
  
positive.code:     var siblings = $A(thisArm.parentNode.getElementsByTagName("LI"))
  
      updateMoveControlVisibility('arm', thisArm.id.split('-')[1], thisArm, siblings)
      updateDeleteControlVisibility('arm', siblings);
  }
  
  function updateAllArmsControlVisibility(epochId) {
      var armItems = $$('#epoch-' + epochId + '-arms li');
      armItems.each(updateArmControlVisibility)
  }
  
  function createStudyControls() {
  
negative.code: <%@page contentType="text/javascript" %>
  <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
  function createAllArmControls() {
      $$('#epochs li.arm').each(function(li) {
          createArmControls(li)
      })
      $$('#epochs ul').each(function(ul) {
          _updateAllArmsControlVisibility(ul.id)
      })
  }
  
  function createArmControls(armItem) {
  