If I'm typing a long message, researching something while trying to answer a question, just reading through a long thread, or doing something in the background, after some time, every single message that was previously unread becomes read and it's a pain to find out which messages have not been read yet. It seems to happen after about 15 or so minutes. Could this be increased to at least an hour, or, preferrably, up to 3 hours or even when the browser is closed?