fwiw, I switched to the Human theme a few months back, and this problem hasn't reappeared. I suspect it was something to do with the H2O- gtk2-Amber theme.
-- notification-daemon using 237MB of memory https://launchpad.net/bugs/67129 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
