def newEntries = childEntries()
        newEntries.remove(indexOfSelectedChild)
        return ChildMapFactory.childMapFromSorted(newEntries)
    }

    CHILD getNodeWithIndexOfSelectedChild(ChildMap<CHILD> newChildren) {
        int index = indexOfSelectedChild
        return childEntries(newChildren).get(index).value
    }

    String getCommonPrefix() {