This is useful, but quick tip: don’t update the history every single time the slider is updated! It will add a bunch of items to the history and make it hard to go back.
Additionally, the “Seriously?” that pops up with some color combinations causes huge amounts of annoying and distracting UI jitter. Please get rid of it.
Or if not get rid of it (It is fun to point out that it is uniquely bad,) make it not jitter! :)