At the moment, the disabled color of the slider is theme.palette.grey[400]. Other inputs use theme.palette.action.disabled (also used e.g. here) and theme.palette.text.disabled.

The Slider should use theme.palette.action.disabled as well.

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

The Slider uses theme.palette.grey[400].

Expected Behavior 🤔

The Slider should use theme.palette.action.disabled.

Steps to Reproduce 🕹

Example showing that theme.palette.grey[400] is used: https://codesandbox.io/s/material-demo-qpzdk

Note: I've forced the color with !important for the screenshot above.

Actually, this demo shows another problem with the current style system - the custom disabled style is not applied, because the css specifity of the default disabled class is higher than the one of the custom class - is this wished? Should I create another issue for this problem?

Steps:

1. Create a custom theme to see the difference between grey[400] and action.disabled
2. set disabled to true

Context 🔦

We edit some values of the palette, which leads to a difference between grey[400] and actions.disabled. All disabled inputs have the same color, except for the Slider component.

Your Environment 🌎