code: public void propertyChange(PropertyChangeEvent evt) {
          // monitor "beanContext" property
          if ("beanContext".equals(evt.getPropertyName()) && contains(evt.getSource())) {
              BeanContext bc = (BeanContext) getPeer();
              if (bc.equals(evt.getOldValue()) && !bc.equals(evt.getNewValue())) {
                  internalRemove(evt.getSource(), false);
              }
          }
      }
docs: This method gets called when a bound property is changed.
  
  @param evt A PropertyChangeEvent object describing the event source
  and the property that has changed.