if you open the MP chat window with the hotkey and decide you don't want to chat , you cannot close the window without putting some kind of input and hitting send...
Suggestion:
MP Chat should auto POP up when opponent receives his turn IF a message was typed by preceding player. ( I have no idea if my current opponent is seeing all my clever messages or ignoring them
EDIT: additional change needed:
my opponent responded to a chat and typed a sentence , however I can only see a small part of it.....
