That has the worst scrolling breakage I've seen for a very long time, on FF mobile at least.
The drilling feels smoother than I remember, but I could be misremembering.
It might help to put some sort of solid or mildly transparent background behind the color wheel so that when content scrolls up it appears to disappear behind the color wheel instead of being right there behind it competing with it visually.
Edit: to be specific, I was referring to that fiddling with the wheel also happens to scroll the text.