In a version change transaction:

store = db.createObjectStore("store");
db.deleteObjectStore("store");
store.put(0, 0); // throws InvalidStateError since object is deleted

But consider:

store = db.createObjectStore("store");
store.put(0, 0);
store.openCursor().onsuccess = function(e) {
  var cursor = e.target.result;
  if (cursor) {
    db.deleteObjectStore("store");
    cursor.continue();
  }
};

The behavior here does not appear to be specified. It seems to me it should also throw InvalidStateError. This could be specified by adding to the operation descriptions for IDBIndex continue, advance, update and delete:

"If the cursor's source or effective object store has been deleted, the implementation MUST throw a DOMException of type InvalidStateError."

(The same would apply to operations on an index if its object store is deleted. That also seems underspecified.)