When a battle is underway while playing in window mode, if you move the window via the window title bar, the game will lose connection with the server and eventually lead to a disconnect. This does not happen in harbor, only during battle.

The problem is that, unlike many other games that run in window mode, the mouse cursor isn't locked within the boundaries of the window. So if I am trying to left click somewhere near the top of the screen, I run the risk of accidentally clicking on the window title bar and slightly moving the NF2 window, disconnecting me from battle.