items?: Array<TreeItem<T>>;
level?: number;
onContextMenu: (event: React.MouseEvent<HTMLElement>, item: TreeItem<T>) => void;
render: (item: TreeItem<T>, level?: number) => ReactElement<{}>;
showSelection?: boolean | ((item: TreeItem<T>) => boolean);
items?: Array<TreeItem<T>>;
level?: number;
onContextMenu: (event: React.MouseEvent<HTMLElement>, item: TreeItem<T>) => void;
render: (item: TreeItem<T>, level?: number) => ReactElement<{}>;
showSelection?: boolean | ((item: TreeItem<T>) => boolean);