When Rectangle Select is used and Cut is executed the transparent background appears. I would like to have white background in 99% of time.

The same problem Rectangle Select and Move Selected Pixcels - background becomes transparent, I need white background.

The same problem with Eraser. When erasing some part of the picture I would like to have a white background, not transparent.

Default white background is by default in MS-Paint, Gimp etc. I think most of the non-expert-image-editing-users expect white background, so I think white background should be default selection.

I don't know how to implement this - some users need transparent (if using image layers), some users need white color. Maybe there should be some general settings to set and preserved when Pinta restarts just like Edit | Palette should be Edit | Default Background and then radio button sub-selections: white, transparent, secondary color,

Maybe now is time to implement Edit | Preferences and this to be first setting in it.