Here's an AI rundown - not guaranteed to be 100% accurate...
"DrawPad does support a gradient project background. NCH’s help says the project background can be set to a gradient using the background controls, with options for linear or radial gradients and direction/stops adjustments.
What to do
- Open the background settings for the project, not just a shape or layer.
- Look for the Gradient option in the background section.
- Choose Linear or Radial, then adjust the colors and stops.
- Make sure your artwork is actually on top of that project background, not on a separate rectangle layer.
Why your eraser is not matching
If you made a gradient rectangle as an object, it is still just a shape. Erasing part of another image will reveal the canvas/project background, not that rectangle, unless the rectangle is truly the background layer. So the fix is to set the gradient at the project background level, or place the gradient as the bottom-most layer and keep it behind everything else.
Practical workaround
If DrawPad’s UI only shows solid color or pattern where you expected a gradient, the gradient may be available in the color picker or background controls rather than the quick background menu. If you still cannot find it, the safest workaround is to place a gradient image as the bottom layer and use that as the visual background. That way, transparent or erased areas reveal the gradient you want."