Hi,
I found a weird issue in PaintDotNet 4.2.5 with last current Nvidia driver 441.12 and [3D Settings / Image Sharpening] enabled in NVIDIA Control Panel
GeForce Experience v3.1.20.57
The issue is fixed by disabling this option : set to <Off> in NVIDIA Control Panel
I will upload pictures for this issue
To reproduce the issue having enabled Image Sharpening] enabled in NVIDIA Control Panel
Launch PaintDotNet 4.2.5
Select Paint Bucket tool
Fill the background with black color
Regards