Provide a tabledrag-handle that is visible in Windows high-contrast mode

I'll look into this and check the alternatives.

Doesn't the icon has to be the same fill color as the text ? Now the fill color is #000 (claro.tabledrag.es6.js line 1711)

If you want to use the brighten filter, maybe the article on https://css-tricks.com/solved-with-css-colorizing-svg-backgrounds/ will help:

Icons with a fill color of #000, or rgb(0,0,0) will not brighten. You need to have a value greater than 0 in any of the rgb channels. fill: rgb(1,1,1) works great with a high brightness value such as brightness(1000), but even brightness(1000) will not work on pure black. This is not an issue with light colors and white.

This is a quick start to this problem. I don't know if this is heading in the right direction.
The solution is inspired by this article on how to fix this problem.

Our icon system sets fill="currentColor" on each <svg>, and then CSS changes that element’s color to change the icon’s fill. Since High-Contrast Mode overrides the color of each element to ensure it shows up on its background, that means the fill will be similarly overridden. Bam! Guaranteed contrast.

Good job!

It looks nice in the 4 high contrast profile in windows with Edge and also in firefox.

Rerolled the Patch.

Hi,

I have changed post-processed CSS file as well as source file.

Thanks,
Ren

Committed bdcfe6c and pushed to 9.0.x, 8.9.x and 8.8.x. Thanks!