Can't change key for push to talk

The option above, the key to open/close text chat, says that it can’t be rebound. When I go to the push to talk button, it says “Set key for Push to Talk.” However, the box on the right is grayed out. I’d really like to be able to rebind this to a different key than what it’s currently on.

This is a known issue OP and is being worked on. Already been noted in the development blogs