In some theme, there’s already have background for the Header which hold both Logo and the Menu, so maybe you don’t want the background of NOO Menu conflict with the background of the Header. It’s good news that on NOO Menu, you can easily set transparent background.

If you look closely on the color picker of the Menu Bar background color, you’ll see that there’s setting for the transparent. It’s the far most column on the right side of the color picker popup, please set the transparent to maximum to have the Menu Bar transparent.