After installing LXDE to my Ubuntu 13.10 system, the notifications tooltip theme changed and it remains after uninstalling LXDE.
Also before that, pressing Fn + Arrow Keys in my laptop I could change the volume and brightness settings and a tooltip would show up indicating the current levels, but now that doesn't show anymore.
sudo apt-get install dconf-tools
) and then runningdconf reset -f /org/compiz/
in terminal.