I don't know if it was mentioned already but I would be very happy to see flak smoke puffs even after I look somewhere else and then back to where I last saw them.
That would be very helpful in identifying enemy location very quickly so that I won't have to wait for a new flak to appear. I know that they can hang in the air for quite a long time but they keep disappearing when I'm not looking even for a brief moment.

Apart from this trifle WOFF makes me very happy. Thank you OBD!

P.S. I noticed that the disappearance somehow depends on the distance. Close puffs stay right where they were while distant ones disappear as soon as I'm not looking at them