Hope someone can help - we will be using the chat activity for the first time this week and did some testing today.
I am a bit confused as the screen we can see does not look similar to that I see in the documentation - there is no theme button or talk option against the users. In fact we initially used Safari as a browser and found ti wasn't even showing the messages on the main panel (though does so in Firefox and Chrome). In the accessible screen messages do not appear unless you keep clicking on refresh.)
We are running 3.5+ and I made sure I was looking at the documenation for that version.