Index -> Interface -> Lobby Chat -> Additional Commands
In any chat window, you may also use the following keys:
UP ARROW and DOWN ARROW: Scroll through the previous messages you have typed.
LEFT ARROW and RIGHT ARROW: Move the cursor left or right within the message you are currently typing.
HOME and END: Move the cursor to the beginning or end of the message you are currently typing.
SHIFT-LEFT ARROW and SHIFT-RIGHT ARROW: Highlight text to the left or right of the cursor. (You can also highlight text using the mouse.)
CTRL-C: Copy the currently highlighted text.
CTRL-X: Cut the currently highlighted text.
CTRL-V: Paste the currently highlighted text.