I have several mostly transparent layers in the project, with white background layer.
Whenever I select an area on the top layer, copy-paste the selection and move it around, something odd occurrs. The selection area seems to also copy the background layer (not other layers) and a solid white block with the actual part of the top layer in the middle moves around. amazingly this white area still is below other layers, it only seems to interact with the top layer.
If I should turn the backgroud layer to be not visible (tick in the layer menu) the white block turns checkered as if to indicate it is transparent, yet it still blocks things in the top layer.
What has happened to my Paint.NET? I do not recall such behaviour in the past.