Chat window closing randomly on login

[Emile]

I've been noticing lately that my "chat 3" window will sometimes be closed out when I log in, forcing me to create a new one and re-assign filters to it. Any idea what would be causing this?

[gcobb]

I've gotten this since the last patch, too. 'Locking' the windows hasn't helped, and for whatever reason the window's right-click menu will no longer let me set one window exclusively to 'Tells.'