Property Index.
| Idx_ParentNode | The node whose children will be displayed in this list. |
| Idx_Filter | If specified, causes the list to display only nodes of this type. |
| Idx_ButtonStyle | The style for the buttons that make up the list. |
| Idx_SelectOnClick | Whether to update the selection when the user clicks on a button. |
| Idx_SelectedNode | The currently selected node. |