The .panel on the right doesn’t do overflow, so on not-enormous screens, some of the sliders are hidden from view. Decovar with fifteen sliders is the easiest to see this on—if the viewport is less than about 1550px high, you’ll miss some of them.

I won’t offer suggestions on fixing that, because the straightforward solutions do damage in other ways; a more carefully thought-out solution will be required.

(Firefox Nightly, Windows.)