Here's a easy way of doing it
(Pretty sure this will work!)
Interface > AddOns > ChatAlphaBye
- ChatAlphaBye.toc
Code:
## Title: ChatAlphaBye
## Version: 1.0
## Author: khurzog
## Credits: Phanx
ChatAlphaBye.lua
- ChatAlphaBye.lua
Code:
DEFAULT_CHATFRAME_ALPHA = 0
Save and play!