Thanks a lot Carole for the detailed and excellent explanation and help!
I already worked too with magic wand, less with freehand selection. I looked at your tutorial and flew over the help in PSP, chapter “modifying selections”. Working with the eraser I discovered a few days ago by accident the right mouse click, that helps a lot if you erased a bit too much. But sometimes there are just very small pixels which are a challenge when you work with the mouse.
That all needs to be trained. Work doesn’t go out :-)!