I've just tried this out and it works as advertised. Chief advantage is that your view doesn't freeze while your typing in chat.

https://forum.il2sturmovik.com/topic/68096-il-2-chatbox-improved-chat-functionality/?tab=comments#comment-1040394

This is pretty cool!

Cool to see a chat macro ability, although more than 2 canned message choices would be nice.  Always missed the feature from RB3D.  👍

I've posted in the IL2 forum asking the developer of Chatbox to provide the option to change keybindings in the ini file. As it stands, I don't think it's possible.