This is about etiquette, which some online players should learn about. Feel free to add. Maybe there should be some guidelines to online play, some social tutoring, to assist those weak in this area.
1. It is very rude to not allow someone to chat during the game, especially when it is in response to something posted by the other, in general. Also, there are times when one may be trying to explain that one may have to retire for some reason or another and is politefully making this reason known.
I wish that there were a way to lock the chat box so that one could finish typing without the other player being able to make the chat box go away. This is very frustrating. However, this is more of an etiquette problem than it is a bug in the game.
2. It is considered inappropriate to join a game and then be constantly swapping applications.
Those are my thoughts.