private boolean isEnabled() {
    if (myLayoutTreeComponent.isSortElements()) {
      return false;
    }
    final PackagingElementNode<?> node = myLayoutTreeComponent.getSelection().getNodeIfSingle();
    if (node == null) {
      return false;
    }
    final CompositePackagingElementNode parent = node.getParentNode();
    if (parent == null) return false;

    final PackagingElement<?> element = node.getElementIfSingle();
    final CompositePackagingElement<?> parentElement = parent.getElementIfSingle();
    if (parentElement == null || element == null) return false;
    final List<PackagingElement<?>> children = parentElement.getChildren();
    final int index = children.indexOf(element);
    return index != -1 && 0 <= index + myDirection && index + myDirection < children.size();
  }
private boolean isEnabled()