This is probably the same as https://bugzilla.gnome.org/show_bug.cgi?id=730763. Could you please verify if you experience the same symptoms as there (e.g. focus out repaints the screen; the timestamp printed by a "date" reveals that it's executed as soon as you hit Enter, even though the display is not yet updated...)?
I haven't faced this bug for a while now. I suspect it's a problem with some underlying component (X, Gtk?) that's probably been fixed in the meantime. (Just for the record: I am using the latest Ubuntu.)
