code: function(o) {
      if(o && (o.ownerDocument == document)) {
          return (Dom.hasClass(this.getTdEl(o),DT.CLASS_SELECTED) || Dom.hasClass(this.getTrEl(o),DT.CLASS_SELECTED));
      }
      else {
          var oRecord, sRecordId, j;
          var tracker = this._aSelections;
          if(tracker && tracker.length > 0) {
              // Looking for a Record?
              if(o instanceof YAHOO.widget.Record) {
                  oRecord = o;
              }
              else if(lang.isNumber(o)) {
                  oRecord = this.getRecord(o);
              }
              if(oRecord) {
                  sRecordId = oRecord.getId();
  
                  // Is it there?
                  // Use Array.indexOf if available...
                  if(tracker.indexOf) {
                      if(tracker.indexOf(sRecordId) >  -1) {
                          return true;
                      }
                  }
                  // ...or do it the old-fashioned way
                  else {
                      for(j=tracker.length-1; j>-1; j--) {
                         if(tracker[j] === sRecordId){
                          return true;
                         }
                      }
                  }
              }
              // Looking for a cell
              else if(o.record && o.column){
                  sRecordId = o.record.getId();
                  var sColumnKey = o.column.getKey();
  
                  for(j=tracker.length-1; j>-1; j--) {
                      if((tracker[j].recordId === sRecordId) && (tracker[j].columnKey === sColumnKey)){
                          return true;
                      }
                  }
              }
          }
      }
      return false;
  }
docs: Returns true if given item is selected, false otherwise.
  
  @method isSelected
  @param o {String | HTMLElement | YAHOO.widget.Record | Number
  {record:YAHOO.widget.Record, column:YAHOO.widget.Column} } TR or TD element by
  reference or ID string, a Record instance, a RecordSet position index,
  or an object literal representation
  of a cell.
  @return {Boolean} True if item is selected.