>>You're confusing an object in a collection with collection itself. You still have read-only access to the collection.
>>The same is true for an objects in an array. You can change the object properties but not the array item it's stored in.
>O!
>I just misinterpret your answer.
>I read it as "Everything is read-only", not just the collection itself. Sorry.

It's my fault because I didn't explain in my original message which part is 'read-only'.