There’re several GUI tools for configuring the Launcher appearance in Unity 3D. But for Unity 2D, it’s kinda difficult.
This tutorial shows how to change the Launcher back-color and transparency by a little change on the code.
NOTE: YOU MUST KNOW WHAT YOU ARE GOING TO DO BEFORE
First, make a backup of
/usr/share/unity-2d/launcher/Launcher.qml. Then edit this file with your favourite editor, for example:
gksu gedit /usr/share/unity-2d/launcher/Launcher.qml
rectangle to find out following section:
Now change the color: “black” & opacity: 0.66, and it will take effect at next login.