Unfortunately, the value is False in the customize UI interface but the button is still showing. Actually, it is showing "Déconnecter" and not "sign out" because we use it in french. I wonder if that could give you an clue to what the problem is...

 

Anyway, right now, when you chat, you have 2 buttons (not considering the format functions): "Envoyer" (send) and "Déconnecter" (sign out). We just want to keep the send button because we don't want to allow users to disconnect from this interface.

 

Hope this clarifies my situation. Thnak you!