The first edit makes the value local

Fictional sample. Values and pseudocode illustrate the mechanism; they are not evidence from a running product.

English source · Russian source

Keep the glow. Change the shadow.

Layout owns the original

Glow + shadow

Shape owns the edited value

Glow + new shadow

Illustrative command

const local = expand(inherited);
const next = patch(local, { shadow: newShadow });
shape.effects = next;
  1. Layout owns the original → Shape owns the edited value: inherits