This is a patch to discuss (not to be landed yet) the possibility of making the window color lighter. I feel like a lighter color would be better suited, especially as soon as D27669 lands. I tried to select a gray shade that still is visually different to the views background color. See screenshots:
Before:
{F8177106}
After:
{F8177109}
With the patch (nb, simulated with kvantum by making the window inactive - in this screenshot, it's a bit lighter than what it will actually be):
{F8177110}