code: public void setDependentStateListener(BaseListener dependentStateListener)
      {
          if (!(dependentStateListener instanceof FileListener))
              dependentStateListener = null;
          else if (this.getOwner() != ((FileListener)dependentStateListener).getOwner())
              dependentStateListener = null;
          super.setDependentStateListener(dependentStateListener);
      }
docs: Enable state is dependent on this listener.
  @param dependentStateListener The listener to get the enabled state from.