private synchronized ExplorerTreeNode addChildAt(final ExplorerTreeNode parent,
                                                     final ExplorerTreeNode child,
                                                     final int position) {
        return addChild(parent, null, child, position);
    }
Get the root node containing a particular node, or the node itself if it is a root node.
stroom-explorer/stroom-explorer-impl-db/src/main/java/stroom/explorer/impl/db/ExplorerTreeDaoImpl.java