docs: void firePropertyParentChanged(TreeNodeParentChangedEvent event) {
  		if (this.nodeListeners != null) {
  			for (final TreeNodeListener listener : this.nodeListeners) {
  				if (listener != null) {
  					listener.treeNodeParentChanged(event);
  				}
  			}
  		}
  		final N parentNode = getParentNode();
  		if (parentNode != null) {
  			parentNode.firePropertyParentChanged(event);
  		}
  	}