Some of you found that after launching the game, text boxes would not take keyboard input — no login typing, no chat — until you clicked another window and came back. Several of you even worked out that alt-tab trick yourselves. Resourceful. You should never have needed it.
The cause was a quirk in how the Steam Overlay hooks into the client: the game window looked focused, but keyboard focus never actually arrived. The client now performs that focus handshake itself — on launch, and again every time you return to the window, including after closing the Shift+Tab overlay.
The update downloads automatically the next time Steam launches the game — nothing to do on your end. If typing ever plays dead again, the old click-away-and-back still works while you tell us in Discord — but it shouldn't.