Compton is a standalone lightweight compositor for X (the graphic server on Linux systems). It provides 2D graphical acceleration and this allow us to drop shadows under the windows, make elements fade as they (dis)appear, draw (semi)transparent menus and notifications, etc.
We’re going to installing Compton from a PPA (only up to Lubuntu Utopic, from Vivid, or 15.04 it’s included in the official Ubuntu repostories). Open LXTerminal and type the following commands:
sudo add-apt-repository ppa:richardgv/compton
sudo apt-get update && sudo apt-get install compton
Now, if we want it to execute on every startup, edit the session file (open LXTerminal and paste “sudo leafpad /etc/xdg/lxsession/Lubuntu/autostart” without the quotes) …and add the following line:
@compton -c -r 16 -l -24 -t -12 -G -b
Don’t forget to include the “@” symbol, or it won’t work. These parameters are my Compton test, play with them to fit your own configuration. And it’s done! Now re-login onto your Lubuntu desktop (or execute “compton -c -r 16 -l -24 -t -12 -G -b && exit” at LXTerminal for immediate testing!