In many cases there is a need to limit access to the Parent's children. Currently it requires to extend Parent or Region and handle all layout and related stuff manually. This is inconvenient.

I propose to implement CustomNode which has all the features of encapsulated Node object but doesn't provide access to its children from outside.

So the following two nodes behave exactly the same way:

new CustomNode() {
  {
    setNode(new StackPane());
  }
};

and just:

new StackPane();