Buttons that are also active and work are Emoticons, Formattings, Nickname, Subject, History, Advanced Functions.
Right click on banner:
disabled: Nickname, Subject
enabled: History, Advanced Functions (minimize on close)
Emoticons
Join to a chat room.
Change status to offline.
Go back to chat room dialog.
Insert emoticons.
Formattings
Join to a chat room.
Write anything.
Select all or partial of the written text.
Change status to offline.
Go back to chat room dialog.
Change text format.
I guess any button is to be disabled except History and Advanced Functions which are also available on right-click on banner, but these two buttons can be disabled, too.