Hmm.... I tried this:
m_ChatText = "Hello!";
MessageBox(m_ChatText);
m_ChatText += char(13) + char(10);
MessageBox(m_ChatText);
m_ChatText += "How are you?";
MessageBox(m_ChatText);
The output is:Hello!
Hello!|-
Hello!|-How are you?
Carriage return, line feed does make sense but it isn't working, at least not how I am implementing it in the above.
So I tried using both escape sequences /r/n which does make a newline.