how do I turn the ingame chat hud (PC) back on?

Since yesterday I somehow managed to get rid of the in game text chat window on PC. Meaning it does only show when I hit ENTER and type a text the hud opens and I see the message being sent.

But a few seconds thereafter it is turning invisible again. There surely is a keybinding to render it visible again, but I did not find it under options so far.

I seam to be able to send orders though (at least I hear my soldier talking)

I haven't changed my nickname - so I supposed it is not some nick filter kicking in, also since i am able to type and send stuff.

After hitting ENTER I am also able to TAB through the chat channels still.

I read the old "chat" related threads but they do not seam to cover my issue which lets me hope I only stupidly manually turned it off.