message: Check set lengths
diff: @@ -282,6 +282,10 @@ function computeNewItems(oldStores: DimStore[], oldNewItems: Set<string>, newSto
  * Compute if two sets are equal by seeing that every item of each set is present in the other.
  */
  function setsEqual<T>(first: Set<T>, second: Set<T>) {
  + if (first.size !== second.size) {
  + return false;
  + }
  +
  let equal = true;
  for (const itemId of first) {
  if (!second.has(itemId)) {
  