Mr Anonymous here,
(can't imagine why the 'from' line goes away like that . . .)
I tried the chat from work yesterday (slow day) and got the same phenomenon. Worse even -- had to shut down and restart.
I suspect the Java applet is still running when you leave the page and it continues to try to connect with the chat server even though it has lost the focus. Maybe all it needs is a "Disconnect" button.
Mark