static void jDynamicTree_addToNode(final JTree tree, fO node, fO child) {
  swing {
    DefaultMutableTreeNode n = jDynamicTree_findNode(tree, node);
    if (n == null) ret;
    if (jDynamicTree_isInDummyState(n)) ret;
    n.add(jDynamicTree_newNode(child));
    ((DefaultTreeModel) tree.getModel()).nodesWereInserted(n, new int[] {n.getChildCount()-1});
  }
}