It works well, and the colors it chooses are quite good. Still, when opening a new tab, there is a momentary flash of white, which then reverts to normal empty dark gray. It's quite jarring. The flash doesn't happen when the extension is disabled. This couldn't be solved with userChrome.css nor with userContent.css customizations. Nor did setting the browser background color in about:settings help. Can you look into it, please?