Tree is not rendering when adding element in typescript.

# Reporting a Bug?

Please include either a failing unit test or a simple reproduction. You can start by forking the [CodeSandbox example](https://codesandbox.io/s/wkxvy3z15w)

# Requesting a Feature?

Provide as much information as possible about your requested feature. Here are a few questions you may consider answering:
* What's your use case? (Tell me about your application and what problem you're trying to solve.)
* What interface do you have in mind? (What new properties or methods do you think might be helpful?)
* Can you point to similar functionality with any existing libraries or components? (Working demos can be helpful.)

Start with the linked CodeSandbox example and reproduce the failure when adding an element in TypeScript. The issue names no source file or test, so trace the rendering behavior from that reproduction; done means the tree renders after the element is added and a regression reproduction or test is provided.

Written by the indexing model from the issue text.