Screen flicker when near-full moon is just outside screen rect

[gzotti]

Seen in Firefox, with FoV about 20...10 degrees: When the moon (almost full in my case, maybe also in other phases) is just outside the screen rectangle, the sky background appears to flicker. Something in the auto-adaptation code?

[xalioth]

Thanks Georg, I can reproduce the issue. It's really a sensitive code, so I am quite reluctant to change this ..