QPalette::Base is translucent in Windows 11

Hi, 

I find that QPalette::Base is a translucent color on Windows 11. I would expect this to be a solid color (for example, white, when the system theme is light).

This causes problems during painting, as if I paint using the base color on top of a widget whose background is also a base color, the colors overlay each other creating a grey hue. 

Steps to reproduce:

qDebug() << qApp->palette().base().color();

Output:

QColor(ARGB 0.701961, 1, 1, 1)

I assume this is a bug, but not sure... It causes problems if I try to paint on top of a widget with base color background, as I would expect the base color in my painting to be invisible, but instead the alpha gets multiplied and it shows up as pale grey. In general I would expect the "base" color to be a solid color rather than a transparent color.

I've attached a screenshot with code showing how widgets with a base color generate grey areas. I would expect this widget to be entirely white.

Best wishes,

Mick