I have committed a theme (https://addons.mozilla.org/en-US/firefox/addon/breeze-dark-plasma-5/) to match Breeze Dark of Plasma 5. I have chosen #232629 as background color. From the preview, I expected this to be the color for active tabs. However, my active tabs now have the color #838689. I wonder where this color is coming from. Actually, the theme now is the same as https://addons.mozilla.org/en-US/firefox/addon/plasma-5-breeze-dark. The initial reason for me to create a theme was to replace the gray active tabs of that theme by darker ones.