anchor.diff:              for (var i=0; i<=bins.length; i++) {
                   count.push([]);
               }
  +            count.push([]); //unknown
               
               for (var r=0; r<rows; r++) {
                   var caseId = dt.getValue(r,0);
                   if (filter && !caseIdsFilter[caseId]) continue;
                   var v = dt.getValue(r,col);
  -                if (v==null) continue;
  -                var i=0;
  -                for (; i<bins.length; i++) {
  -                    if (bins[i]>=v) break;
  +                var i;
  +                if (v==null) {
  +                    i = bins.length+1;
  +                } else {
  +                    for (i=0; i<bins.length; i++) {
  +                        if (bins[i]>=v) break;
  +                    }
                   }
                   count[i].push(caseId);
                   caseIdHistMap[caseId]=i;
  
positive.code:             }
              hist.push(['>'+bins[bins.length-1],count[i].length]);
              histCaseIdMap[i]=count[i];
          } else {
              var count = {};
              for (var r=0; r<rows; r++) {
                  var caseId = dt.getValue(r,0);
                  if (filter && !caseIdsFilter[caseId]) continue;
                  var v = dt.getValue(r,col);
                  if (v==null) continue;
                  if(count[v]==null) count[v] = [];
                  count[v].push(caseId);
              }
  
negative.code:             if (fire)
                  func.call(window,this.caseId);
          },
          fireSelection: function(caseId,source,targets,forceFire) {
              if (!forceFire&&compareAssociativeArrays(caseId,this.caseId)) return;
              //$('#submit-patient-btn').attr("disabled", caseId==null);
  
              this.caseId = caseId;
              for (var listener in this.funcs) {
                  if (targets!=null&&(targets!=listener&&!targets[listener])) continue;
                  if (listener==source) continue;
                  var func = this.funcs[listener];
                  func.call(window,caseId);
  