overlay

function · packages/richtext-dom/src/editor-bundle.ts:394

function overlay(
  hostId: string,
  decorations: RichText.DecorationSet,
): Command.Command<Message>

Draws decorations over the editor at hostId, beside what its placement draws, until the next overlay replaces them: decorations an application derives from its own state, such as other people's carets, which a placement's decorate cannot see. Their positions name the document shown, so an application sets them again when that changes. The caret stays put.