When I set the "Field background" color it works properly everywhere except for the location bar in the source Lister toolbar. There, the color mixes with the "File display border - Source" background color.
But the path field almost completely covers the file display border? (At least normally.) If it didn't mix you'd only see a bit of the color around the edges and under the handful of buttons at the sides.
I have lots of buttons in my Lister toolbar, so there's plenty of color to help me distinguish between source and destination. I would very much prefer the location bar background to be white. I understand color mixing as a default setting, but maybe you could make an option under Advanced settings to let us turn off mixing?