In the past IM tabs started to flash and kept flashing when a new message from that IM channel arrived. Now it just flashes once and then turns kind of inverse. While the old behaviour was able to alert while concentrating on the world and chat (peripheral vision), the new behaviour requires active attention not to miss messages. This UI change makes the handling of multiple IMs in parallel to chat and other activities like moving (eg. during hosting in a club) almost impossible. Being busy in chat lets you easily overlook a new message for minutes. This UI change urgently needs at least a preferences setting to switch back to the old behaviour. There is no real advantage to the new behaviour anyway. This is a showstopper for multichannel communications.