New Background Color Doesn't Work

Hi,

I wanted to make a background color shine through –
I went to Row Settings (in the Visual Composer) and down to Opacity.
That’s easy.

However, when I go to Theme Options and add a new color to the theme colors;
for example black, then go back to the image in Row Settings and select black,
nothing happens. In fact, it now mixes with white.

Is there something I am missing?
The opacity works with every background color, except the one I just added.

Laurens.