When Firefox upgraded to Firefox quantum, my custom theme on the toolbars at the top of the browser is no longer showing. When I went to customize the appearance settings it claims that the custom theme I used to see is indeed enabled, but you still can't see it. When you disable it and then re-enable it again, the theme shows up until you click on something and then it disappears again. Are old themes not compatible with the new firefox? Is there a way I get my old custom theme to show up?