It's very buggy.
When the chat is above the title you can only move it sometimes while the stream is loading (also the overlay moves slower than your cursor, which often cancels the movement). Another time the resizing didn't work because the overlay was cropped halfway or the toggle button displayed twice. There are massive lags when you go in fullscreen due to the chat loading.

Je ne vois pas le chat dans mon jeu! Faut-il un overlay spécial avec?