When you join a lot of channels, have the "tabs" configured to be on the left / right side (so it becomes a tree list), it is very hard to see that there has been an action in a channel which is currently not visible. 

Reproducible: Always

Steps to Reproduce:
1. Set the channel list to be on the left / right
2. Join a lot of channels or reduce the window vertical size
3. Have an action (message, event, whatever) happen in a channel that is not currently visible (you'd have to scroll)
Actual Results:  
No easy way to see that there has happened something

Expected Results:  
Have an indicator showing that there has been an action in a channel currently not visible. 

Nice would be some kind of coloured bar at the top / bottom (depending on scroll position) which changes the colour depending on the action that happens. If multiple ones happened: probably highest priority (e.g. highlight over message over event) if possible