The bindContentBidirectional method is completely unaware of previous content bindings and allows situations that cause the bindings to be broken or even log exceptions.

For example:

    public static void main(String[] args) {
        ObservableList<String> a = FXCollections.observableArrayList();
        ObservableList<String> b = FXCollections.observableArrayList();
        Bindings.bindContentBidirectional(a, b);
        Bindings.bindContentBidirectional(a, b);
        a.add("A");
        System.out.println(a + " : " + b);
    }

Will print:

    [A, A, A, A] : [A, A, A]

When there are 3 or more lists involved, the problem can get so bad that `IndexOutOfBoundsException` is thrown somewhere in the code handling the syncing of the lists (which is caught and only logged to the console while leaving the list contents badly unsynced).

I've made a PoC that rejects circular bindings and overlapping bindings when they're detected.