Like in skype when somebody else is replying you will see the message:
"Lee Prosser is writing ..." in the chatwindow.
Would be nice if we could get this kind of similar warning so that we know when someone is busy writing a response. (from a DM point of view this allows me to judge when to reveal or action certain events)
This was originally going to be the case, but it was slightly more complicated to do, we will look into doing this additional change in the next release.
This change should now be in the next release.
This functionality has been implemented however it has been simplified to just be a bar at the bottom of the chat window to notify you who is typing. This will pop up when someone is typing then disappear when they have stopped typing for a period of time (currently 10 seconds).
If we were to do it as per Trillian does it then a large portion of the screen could be potentially taken up by a few players with just "..." as their content so it would be harder to see the important messages, if this there is some specific design change required we can do that as a cosmetic update later.
This will be put live in the next release.