anchor.diff:        item.classes.toggle(this.selectedClass, isSelected);
       }
       
  -    // TODO (zoechi) I think we could require that a published property (attribute) is used.
  -    // than we can drop reflection
       //(egrimes) Note: It looks like Polymer.js adds the property dynamically to 
       //the item. PolymerSelector defaults selectedProperty to 'active', so users 
       //will have to explicitly set selectedProperty to an empty string to keep 
       //from blowing up. I'm not sure that's reasoable.
       if (this.selectedProperty != null && this.selectedProperty.isNotEmpty) {
  -//      reflect(item).setField(new Symbol('${this.selectedProperty}'), isSelected);
  -      item.attributes[selectedProperty] = isSelected.toString();
  +      //Note: Reflection is required to work properly with checkboxes
  +      reflect(item).setField(new Symbol('${this.selectedProperty}'), isSelected);
       }
     }
     
  
positive.code:         } else {
            this.selected = s;
          }
          this.asyncFire('polymeractivate', detail: item);
        }
      }
    }
  
negative.code:   
    void selectedChanged(old){
      //(egrimes) Note: Workaround for https://code.google.com/p/dart/issues/detail?id=14496
      Timer.run((){_updateSelected();});
      //this._updateSelected();
    }
    
  