Chat doesn't scroll down when it should

[taoeffect]

Problem

1. Create user u1 in browser 1, create group, open chat
2. Make the window short enough so that when there are at least 5 messages, the scroll bar will appear
3. Send enough messages to make the scroll bar appear
4. Open another browser (Browser 2), log in as u1, and send messages to the chat

You will see that in Browser 1 the new messages are not automatically visible and you have to scroll down manually.

Solution

Fix.