How is the erase tool supposed to work?
I often try to use it to get rid of grey margins and black spots on scanned document pages. But in some unpredictable cases, the eraser just produces some kind of grey smear; in other cases, it does what I expect it to do: taking the grey away, leaving white "paper".
As I'm struggling with this behavior for 10 or so years now, and I couldn't find anything more than that the eraser erases (https://help.abbyy.com/en-us/finereader/15/user_guide/adjustimage), I suppose it's not a bug, but a feature.
What is the concept of the eraser that I don't get?