Chat bug

What I expected to happen was...:
Change the key to open the chat GUI

What actually happened was...:
The key actually change for a while but disappears a short time after and I must re-apply it in the options

Steps to Reproduce:
1. Change the key to open the chat
2. Then the key disappears and its notified : NONE

I'm not sure of this bug, but happens to me everytimes I try, I don't know in which conditions the key disappear.
Hope you understood this and maybe you'll fix that ! Bye