Requires N:M mapping.
This mapping has 1 multi-map group: several pairings are equally correct there. The code view shows one arbitrary valid pairing, not the only one.
This mapping has 4 all-to-all groups: every node on one side corresponds to every node on the other, and none is deleted or inserted. Each member carries an all N:M badge; selecting one highlights all of its counterparts, in the tree and in the code view alike.
A painting is a person's account of this edit as text, recorded independently of the node mapping - a rendering often has several equally defensible answers where the mapping has one. Deletions and insertions carry no position on the opposite side in a painting, so that panel draws no caret for them.