First open MCC (Mageia Control Center)
Click Hardware tab
Click Configure 3D Desktop Effects
Select Compiz-Fusion
Click on and allow packages to install
Log out
Open CCSM (CompizConfig Settings Manager)
Click Opacity, Brightness, and Saturation
Click New
Type class=Ccsm
Set Value to 90 (90 is what I use, you can use whatever you want)
Also set these
class=Nautilus
type=Normal
type=Dialog
type=DropDownMenu
type=Menu
type=PopupMenu
type=Tooltip
I set them all to 90