Not for the faint of heart. You will have to compile unity from source. There is a script that does this automatically. You have to download this file.
Then open the terminal and cd to the directory you downloaded it to.
- Now type
./build-unity.sh prerequisites
- When finished type
./build-unity.sh clone
Now after it is done cloning, the fun can start. Browse to the directory you downloaded the build-unity.sh file and open the unity folder.
Then open the src folder and open file launcher.cpp
.
Search for this string
gPainter.Paint2DQuadColor (GfxContext, bkg_box, nux::Color(0xAA000000)
You can change the argb hex decimal to any color you want, A = alpha R = red G = green B = blue:
0xAA000000
example 0x88008800 would about equal a green plus alpha
To color the dash, open PlacesView.cpp
and search for
nux::Color (0.0f, 0.0f, 0.0f, 0.9f)
example nux::Color (0.0f, 0.5f, 0.0f, 0.7f) which again equals green plus alpha
- now you can type
./build-unity.sh configure
- and when finished type `./build-unity.sh run
Here's the results

Best Answer
From the terminal, you can use:
to get the current value for launcher opacity and
to set the launcher opacity to
X
.X
must be between 0 and 1.P:S This way is preferred over any other method that used dconf directly.
See also: