@Override
 public void handleEvent(VisualMappingFunctionChangedEvent e) {
   final VisualMappingFunction<?, ?> mapping = e.getSource();
   if (this.mappings.containsValue(mapping)) {
     eventHelper.addEventPayload(
         (VisualStyle) this, new VisualStyleChangeRecord(), VisualStyleChangedEvent.class);
   }
 }
 @Override
 public void removeVisualMappingFunction(VisualProperty<?> t) {
   mappings.remove(t);
   eventHelper.addEventPayload(
       (VisualStyle) this, new VisualStyleChangeRecord(), VisualStyleChangedEvent.class);
 }
 @Override
 public <V, S extends V> void setDefaultValue(final VisualProperty<V> vp, final S value) {
   styleDefaults.put(vp, value);
   eventHelper.addEventPayload(
       (VisualStyle) this, new VisualStyleChangeRecord(), VisualStyleChangedEvent.class);
 }
 @Override
 public void addVisualMappingFunction(final VisualMappingFunction<?, ?> mapping) {
   mappings.put(mapping.getVisualProperty(), mapping);
   eventHelper.addEventPayload(
       (VisualStyle) this, new VisualStyleChangeRecord(), VisualStyleChangedEvent.class);
 }