E.g. if I click "Ensure right margin is not exceeded" it isn't shown in the example file. Btw. how can I say that a "+" at the end of the line should always go to the next line?
test = A + B +
test = A + B
Yes, it's a known problem that some settings change is not highlighted at the preview. There is a ticket for that but it doesn't have a big priority - IDEA-63047.
Regarding the binary operation sign location - is scheduled for the v.13 - IDEA-80495.