default void removeAllChildren() {
        List<RedUINode> children = new ArrayList<>(getOurChildren());
        for (RedUINode child : children) {
            child.removeFromParent();
        }
    }
Calls {@link RedUINode#removeFromParent()} on each child safely (i.e. without concurrent modification exceptions)
core/src/main/java/mrtjp/projectred/redui/RedUINode.java