Custom categorie breaks focus of last regular category

[rickstaa]

I just tried the custom emojis and categories example of the README (i.e., https://github.com/missive/emoji-mart#custom-emojis). I, however, noticed that when I add a custom category, the focus of the last non-custom category is broken (see video below).

Current behaviour

https://user-images.githubusercontent.com/17570430/189505313-36345fe1-fefd-4216-b54e-0e896b2fb943.mp4

Expected behaviour

The picker should focus on the flag category when clicked.

How to reproduce

1. Clone the example repository https://github.com/rickstaa/custom-emoji-test.
2. Install the dependencies npm i.
3. Start the development server npm start
4. Open localhost:3000.
5. Click on the flag icon.
6. See the focus going to the Octocat icon.

[rickstaa]

I think I found the problem. It looks like that the problem happens when the groups before the end group are not full enough (see gif). In that case, it will always drop to the bottom and select the last group.

https://user-images.githubusercontent.com/17570430/191202861-4bb7d2fc-bccc-4620-aa05-88c7ca8ee27e.mp4

[rickstaa]

Amazing! Thanks a lot! Looking forward to the next release 🚀.