It's because when you open a conversation with a contact, a connection is established with the contact. After a while of the connection not being used, the connection will automatically break. Stuffplug reads this break in connection as the contact closing the window, but it isn't really.
It's nothing to worry about and something that your going to have to live with for now.
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![[Image: rhcpsig38tj.png]](http://img147.imageshack.us/img147/4060/rhcpsig38tj.png)
