Auto Focus

Auto Focus (or Auto-Focus) refers to a chat function that allows the player to make the chat disappear, not reappearing for every message that is received.

To enable Auto Focus: press CTRL+T, click on Auto-Focus (it should turn red), then close the chat and wait. The chat will fade away in a few seconds.
The button is a toggle, so pressing Auto-Focus again makes the chat pop up as usual.