message: Fixed bug with key prop in RuleGroup
diff: @@ -166,7 +166,7 @@ export const RuleGroup = ({
  {rules.map((r, idx) => {
  const thisPath = path.concat([idx]);
  return (
  - <Fragment key={r.id}>
  + <Fragment key={thisPath.join('-')}>
  {idx > 0 && showCombinatorsBetweenRules && (
  <controls.combinatorSelector
  options={combinators}
  